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TRANSCRIPT
Microsoft Windows Server 2003 and Microsoft Windows Storage Server 2003: Meeting the Storage Challenges of Today’s Businesses
Contents
Introduction 2
Microsoft® Windows Server™ 2003 and 3
Microsoft® Windows® Storage Server 2003: Robust Storage Solutions
Storage Challenges 4
The Need for Scalable Solutions 4
The Need for Fault Tolerance 4
The Need for Protected Data 5
The Need for Manageable Solutions 5
The Need to Control Costs 5
Advantages of the Windows 6
Storage Platform
New and Enhanced Storage Solutions 8
VDS for Storage Disk Management 8
VSS for Effective Data Protection 10
FRS for Remote Replication 11
DFS for File Sharing 11
ASR for Rapid Disaster Recovery 12
EFS for Secure Data 12
iSCSI for Storage Area Networking 13
MPIO for Highly Available Data 14
Enhanced Support for SANs 14
Summary 15
Overview of Windows Storage 16
Server 2003
Introduction 16
What is Windows Storage Server 2003? 17
Advantages of Windows Storage 17
Server 2003
The Basics: How NAS Works 19
File Serving Component 19
Hardware Component 19
Storing Component 19
Optimising NAS 19
Windows Storage 20
Server 2003 Features
Networking 20
File Serving 21
Storage 22
NAS Management Software 23
Performance 23
Integrated Snapshots 24
Improved End-User Experience 24
New Features in Windows 25
Storage Server 2003
Volume Shadow Copy Service (VSS) 25
Virtual Disk Service (VDS) 26
Multipath I/O (MPIO) 26
Distributed File System (DFS) 27
NAS Deployment Scenarios 28
File Serving 28
Server Consolidation 28
Local and Remote Site Replication 29
for Business Continuity
NAS-SAN Fusion 29
Summary 30
Related Links 30
Data is a business’s most valuable asset. The rich media
content of static and dynamic Web pages, huge volumes
of email, 24 hours a day, 7 days a week demands of
e-commerce, and the dependence on massive relational
databases have all contributed to the explosion of
mission-critical data. For the system/storage administrator,
managing an organisation’s growing wealth of information has
become an increasingly complex, high-pressure undertaking.
Key to the storage administrator’s success is ensuring that
information is:
Available to those who need it when they need it.
Protected from security risks, system failure or
catastrophic events.
Rapidly recoverable should the need arise.
The system administrator must accomplish these tasks
in the context of rapidly changing storage technologies.
While there are many storage solutions available today,
not all solutions scale well with organisational growth,
nor are all equally capable of delivering cost-effective
high-performance solutions.
The new and enhanced data and storage management
capabilities of Microsoft Windows Server 2003 and
Microsoft Windows Storage Server 2003 are critical tools
in helping system and storage administrators do more with
less. This white paper discusses the storage challenges
that face businesses today and the benefits of using the
Windows Server platform to meet those needs.
Introduction
2
Windows Server 2003, Microsoft’s newest release of the
Windows server operating system, is a multi-purpose server
designed to handle a diverse set of server roles, including
file and print, mail, Web, terminal and directory services. The
integrated storage services in Windows Server 2003 have
been enhanced and expanded to include a number of new
features that help businesses control storage management
costs and increase availability of data. Features such as
the Volume Shadow Copy Service (VSS) and the Virtual Disk
Service (VDS) make it easier to manage and maintain disks,
helping lower Total Cost of Ownership (TCO) especially in
complex multivendor storage environments. Point-in-time
imaging capability through VSS simplifies and speeds up both
backups and restores. And, the Shadow Copies for Shared
Folders feature of VSS enables end users to restore their own
files and folders without IT intervention. High availability is
enabled through multi-pathing and clustering.
Windows Storage Server 2003 is a Network Attached Storage
(NAS) operating system, built upon the Windows Server 2003
operating system. Windows Storage Server 2003 lets Original
Equipment Manufacturers (OEMs) build appliances optimised
for file serving, since applications unnecessary to the file
serving and storage tasks are not activated. Storage Server
NAS devices are headless (without monitor, keyboard or
mouse) and can be managed through a Web-based user
interface. Designed for ease of deployment and seamless
integration into the existing network, Windows Storage
Server 2003 can provide expanded storage capacity to users
on the network in under 15 minutes. The Storage Server NAS
solution is especially appropriate for organisations that do not
wish to put extensive IT resources into setting up multiple file
servers and managing them.
Windows Server 2003 and Windows Storage Server 2003: Robust Storage Solutions The storage administrator in all businesses, large or small, is
faced with a number of key problems:
Ensuring that as an organisation’s data grows, storage
capacity scales to accommodate it.
Ensuring that mission-critical data is well protected from
the risk of hardware failure, security breeches, or disaster;
and that data is available on an on-demand basis.
The sections that follow explore these needs in greater detail.
The Need for Scalable Solutions
Embedded hard drives or directly attached external disks
– referred to as DAS (Directly Attached Storage) – is the
most common way to store data on desktops, workstations
and servers. The simplest solution to the demand for more
storage capacity is to add more hard drives, upgrade to higher
capacity disks, or to purchase additional computers each
with more DAS. While DAS solutions can be effective for many
businesses, they are often only temporary fixes, and result in
a number of challenges for the storage administrator.
Decentralised Data
As the number of DAS systems grows, increasingly, data is
dispersed throughout the company, making it difficult for
users to know what resources exist and where to find them.
This is an especially troublesome problem with data stored
on desktops since, unless individuals allow file sharing, there
is no simple means of making the data accessible to others.
Even with sharing enabled, there is no effective mechanism
to determine exactly where information is stored, or which
document is the most up-to-date version.
Migration of a company’s critical data to a centralised server
helps the situation somewhat since the data can be shared
readily across the network. But as more servers are added to
increase storage capacity (and to provide redundancy in the
event of hardware failure), without a mechanism to unify the
presentation of directories and file shares, users still have the
problem of not being able to find the data that they need – or,
in some cases, even knowing that it exists.
Underutilisation of Storage Resources
Only the computer to which the storage is attached can
access DAS. Effective storage planning requires accurate
predictions about which users and applications will
require more storage capacity, and those resources must
be provisioned before disk capacity is exceeded.
Unfortunately, DAS always scales poorly over the long term.
Some computers inevitably exceed their storage capacity,
while others have excess capacity but no means to share
those resources effectively.
Adding more servers does not eliminate the problem of
inefficient utilisation of storage space between servers.
Storage remains local to each server; thus space may be
available on one server but capacity exceeded on another.
Anticipating growth and implementing storage solutions that
scale with growth remains a problem.
Proliferation of Storage Equipment
Adding servers to meet the need for greater storage capacity
is an effective solution as long as the number of servers
an administrator can handle remains manageable. Servers
must be maintained, backed up and serviced, all of which
rapidly becomes a management headache for the system
administrator. And as long as storage remains attached
directly to the server, each server must have its own directly
attached tape drive for backups; a very costly solution for
equipment that is only in use during the backup and
restore process.
Ensuring Compatibility with Storage Networking
Solutions
The best storage solutions not only meet today’s storage
needs, they also scale well with more advanced storage
solutions, such as Network Attached Storage (NAS) and
Storage Area Networks (SANs).
The Need for Fault Tolerance
More and more businesses rely on making their services
and information available for access 24 hours a day,
7 days a week. Failure in any of a number of hardware
components – storage devices, storage interconnects,
cabling, network interconnects, processors, motherboards
and power supplies – can result in a temporary or permanent
loss of data. Fault tolerance can be achieved through
redundancy of hardware components, and is one means
by which to ensure highly available data.
Storage Challenges
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Redundant Disks
Externally attached storage devices can be made highly
redundant using RAID (Redundant Array of Inexpensive Disks)
subsystems. Redundancy can be achieved in a number of
different ways, including mirroring, which replicates the data
on one disk to one or more additional disks. Should one
disk fail, the system can “failover” to a second disk with the
replicated data.
Redundant Hardware through Clustering
A cluster is two or more computer systems that act and are
managed as one. Clustering allows applications to remain
online, even if a server goes down. Users are redirected to
another computer without any loss of services.
The Need for Protected Data
System administrators must protect data not only from
hardware failure, but also from data corruption, user error
and disasters. The most common means of protecting data
from these problems is through tape backups and restores.
Unfortunately, this solution provides only partial protection.
Poor Protection of Desktops and Laptops
The individual user must back up DAS. However, users are
rarely effective in performing regular backups, and for that
reason, system administrators strongly advocate storing
documents and data that is critical to the company on the
server, where it can be backed up properly.
Open File Backup Constraints
While management of backups can be simplified using a
centralised backup server, the time required to perform
backups conflicts with the demand for continuously available
data. Trying to back up an open file can result in data
corruption. As a consequence, those files must either be
skipped (meaning that the backup is incomplete) or users
must close their applications during backups. Preventing
data corruption during the backup process has meant that
the backup period must be restricted to when users are not
trying to access their files across the network – typically, just
evenings and weekends. As organisations produce more
and more data that must be backed up, the time it takes to
backup data can exceed the nightly or even weekend
backup times.
The Need for Manageable Solutions
System administration can become enormously complex,
especially in mid-sized and large organisations. Administrators
are responsible for managing Web, application and database
servers and for clustering those servers to ensure effective
performance and high availability. They are also responsible
for managing dedicated Storage Networks (SANs) that host
multivendor storage devices, each with a vendor-specific disk
management application. These management consoles are
not standardised, making training and usage unnecessarily
complex. Administrators are responsible for managing
utilities for such tasks as backup, data mining and testing.
Since applications are not storage-aware, managing data
for backup and transport can be a complex and inefficient
process. Finally, although many organisations require multiple
platforms to support various applications, there are increasing
demands that data be shared among users irrespective of
whether they use Windows, UNIX or some other
operating system.
The Need to Control Costs
Organisations are demanding that system administrators
deliver robust, reliable and scalable storage solutions within
a budget that remains flat or has declined. Among the most
effective ways to control costs and still deliver effective
storage solutions is to consolidate resources. NAS solutions
provide a cost-effective means to add storage capacity
while consolidating equipment. As many as 10 and up to 25
file servers can be consolidated into a single NAS device,
depending on the amount of data consolidated. Not only does
this mean that equipment and licensing costs are curtailed, it
also enables the consolidation of related equipment such as
backup devices and the reduction in management overhead.
Solutions that automate or speed up storage provisioning,
backups and general maintenance all decrease the need for
administrator interventions, saving the administrator time and
effort. These costs can be directly passed on to the business,
lowering total cost of ownership and ensuring the most
effective utilisation of existing storage resources.
Both Windows Server 2003 and Windows Storage Server
2003 provide businesses with reliable storage solutions
that are designed to keep data protected, highly available,
and easily managed – without huge capital expenditures.
Windows Server 2003 and Windows Storage Server 2003
help businesses to reduce their total cost of ownership by:
Lowering IT Intervention Costs.
The accidental deletion or overwriting of files has long
been the bane of system administrators charged with the
time-intensive and costly task of locating and restoring
single files from tape. The Shadow Copy for Shared Folders
(SCSF) feature of the new Volume Shadow Copy Service
(VSS) enables users to easily restore their own deleted
files, without IT intervention.
Managing Backups and Restores More Effectively.
As organisations produce more information, backing up
data becomes an increasingly time-intensive and potentially
disruptive operation. Tape backups have the additional
drawback that it is only during the restore process that
data corruption becomes apparent – making data recovery
impossible. With the new VSS, open file backups are enabled,
thus making unnecessary the disruptive practice of shutting
down applications during backup to prevent data consistency
issues. The process of creating Shadow Copies is designed
to ensure data integrity prior to the tape backup process,
thus ensuring that the data is complete, uncorrupted and
able to be restored.
In the case of catastrophic system failures – cases where
the hard drive loses all operating system information and
is effectively stripped down to the bare metal – Automated
System Recovery (ASR) makes possible rapid restore of the
system’s original state possible.
Increasing Availability and Security of Data.
Making data highly available throughout an organisation
requires data redundancy. The VSS allows administrators
to schedule making regular copies of data stored on disk,
and makes it painless for users to access consistent
point-in-time copies of data. Moreover, since only the
changes to the data are saved1, Shadow Copies take up
very little disk space, enabling companies to make copies
of whatever data is needed.
The File Replication Service (FRS) controls replication
and synchronisation of data. This data can be made
highly available to remote sites using the Distributed
File System (DFS).
Managing Multi-Vendor Storage More Effectively.
Multi-vendor storage device management has required
that the system administrator manage each device
independently – and use a different vendor supplied
interface to do so, thus adding another layer of complexity
to the system administrator’s job. With the introduction
of the new Virtual Disk Service (VDS), the system
administrator can use a single interface to configure
storage from multiple vendors. (This solution is fully
implemented in partnership with the storage
hardware vendors)2.
Increasing the Effectiveness of File Sharing.
The Distributed File System helps to make the end user’s
process of locating and accessing files distributed across
an organisation effortless. With the Windows Server 2003
release, DFS has been enhanced to allow for multiple DFS
root directories on each server. This capability means that
it is no longer necessary to add an additional server for
each additional DFS root directory. DFS also offers closest
site selection, ensuring access to the nearest available
copy of the data at the lowest cost.
Advantages of the Windows Storage Platform
1 This is true when using shadow copy capabilities through the operating system. Hardware provider solutions may be different.
2 Hardware vendors create the hardware provider (the component that controls the storage device), and use the VDS application programming interfaces (APIs) to provide hardware-specific VDS functionality.
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Leveraging Existing Network Infrastructure for SAN
Storage. Windows support for iSCSI technology allows
users to connect computers to consolidated storage
devices using existing Ethernet technologies, rather
than having to install a separate Fibre Channel network.
Microsoft’s enabling of this technology will help bring the
advantages of SAN to mid-sized and small businesses
that otherwise could not afford the extra cost and
management of running a separate Fibre Channel network.
SAN technology based on IP also removes the physical
limitations of moving data further than the current 10km
limit imposed by Fibre Channel technology.
In addition to enabling less expensive SAN solutions, the
Windows storage platform now provides better support for
SANs. Administrators can now control volume mounting to
protect volumes from unintentional access. Handling of Fibre
Channel SANs has been improved, as has SAN Host Bus
Adapter (HBA) interoperability, both of which further ease
administration complexities. Lastly, boot from SAN, with
vendor support, is greatly enhanced in Windows Server 2003.
Windows Server 2003 and Windows Storage Server 2003 give
businesses cost-effective, highly manageable and scalable
storage solutions, designed to meet a range of business
needs and helping to ensure that the cost of managing
storage does not exceed storage capital expenditures.
The next section details the new storage features and
enhancements to existing functionality.
The key to reliable storage solutions lies jointly with managing
disks and data effectively. Windows Server 2003 and
Windows Storage Server 2003 provide a number of services
and tools that the system administrator can use to manage
both data and storage effectively, thereby maximally exploiting
a company’s storage investments.
VDS for Storage Disk ManagementVirtual Disk Service (VDS) is new to Windows Server 2003
and Windows Storage Server 2003.
VDS enables storage solutions that are:
New and Enhanced Storage Solutions
VDS is the foundation supporting the Disk Management
User Interface (UI) and a number of scriptable Command
Line Interfaces (CLI) for disk management. VDS enables disk
management of DAS, NAS and SAN devices, and is especially
helpful in simplifying system administration of multi-vendor
storage devices on SANs.
Disks can be housed singly (as is the case with embedded
disks) or grouped together in large storage subsystems. The
disks within a storage subsystem can be configured as:
JBOD systems
JBOD systems are “Just A Bunch Of Disks.” Early disk
management software could format, partition and assign
drive letters to each disk individually. However, prior to
technologies like VDS, there was no means by which to
manage these disks as a unit.
RAID systems
Not only are these disks housed together physically but
also, with the appropriate disk management software, these
disks can be variously configured such that virtual disks
are created across multiple physical disks. So configured,
each virtual disk acts as a single logical unit, numbered for
identification (hence they are referred to as LUNs). Each RAID
type (most commonly RAID 0-5) is associated with a particular
level of data redundancy, which translates into enhanced
performance and data protection. RAID devices can be further
distinguished by where the RAID controller software lies:
Software RAID. The intelligence for creating the RAID
types lies in the host operating system. All processing
control resides in the OS.
Hardware RAID. Control for configuring RAID types does
not lie within the host OS, but is either on an internal RAID
adapter card or it is external to the host computer system,
residing on the external disk subsystem itself.
DISKPART
DISKPART is a scriptable CLI, which provides the commands
for managing the creation, extension and deletion of
partitions on both basic and dynamic (expandable) disks.
The utility can be used to configure both simple volumes
(which span a single partition) and multi-partition volumes
(which can span multiple partitions on a single disk or on
multiple disks). Multi-partition volumes can be configured to
provide different levels (RAID types) of data redundancy for
data protection and performance improvements. Software
RAID devices are controlled by DISKPART.
Scalable Configures storage devices on NAS and SAN
Fault tolerant Configures RAID (mirroring, striping or striping with parity) for data redundancy
Manageable
Provides a single interface for multi-vendor storage3
Controlled mount points for SANs
3 Where supported by hardware providers.
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Volume extension is particularly important in those instances
when a volume has nearly reached allocated capacity but
there is still free unallocated disk space available on a single
disk or RAID array. Volume extension allows for an increase
in the size of the volume, with no loss of data.
DISKRAID
DISKRAID is a scriptable CLI available through the
Windows Server 2003 Resource Kit or the Deployment Kit.
It is used with VDS and vendor-specific hardware providers
to configure virtual disks (logical disks that span two or
more physical disks) on hardware RAID devices.
Multi-Vendor Disk Management
Multi-vendor disk management on SAN systems has, until
now, been a complex undertaking. Configuration of storage
devices on the SAN has previously been through vendor-
specific management applications. These applications are
not standardised, and require that storage administrators be
trained on how to use differing interfaces. VDS overcomes
this lack of standardisation by providing a single standardised
interface by which to manage multi-vendor storage devices.
VSS for Effective Data ProtectionVolume Shadow Copy Service (VSS) is new to
Windows Server 2003 and Windows Storage Server 2003.
VSS enables effective:
The VDS scriptable command line interfaces allow
administrators to automate storage operations across
storage systems from multiple vendors. Using the CLI, the
administrator can create a script to add storage to the
network. Although this script works with multi-vendor storage
hardware, no vendor-specific training is necessary to create
the script. When new drives are added to the storage array,
the administrator can run the script that automatically
configures the disks for use. VDS multi-vendor disk
management requires a “hardware provider” – software from
the vendor that translates VDS abstractions into hardware
RAID specific instructions for configuring RAID sets.
The VSS provides the infrastructure for creating high
consistency point-in-time copies of single or multiple volumes.
The service provides effective data protection to both system
administrators and end users.
Open File Backup
VSS coordinates with business applications, backup
applications and storage hardware to provide application-
aware data management. Previously, there had been no
means by which backup applications could prepare data for
backup – applications either had to be shut down to prevent
data corruption or files were simply not backed up. Now, with
VSS, open file backups are possible and application users do
not have to worry about closing files or being unable to use
their applications.
Data Integrity
With VSS, the storage administrator no longer has to worry
about missing data during the backup process, or about the
possibility of undetected data inconsistencies. If there is a
problem during shadow copy creation, the administrator is
notified immediately of an inconsistency between the original
data and the shadow copy. This enables the administrator
to reschedule shadow copy creation before committing the
backup copy to tape, rather than discovering during the
restore process that the backup had been unsuccessful.
User-Enabled File and Folder Restores
Shadow Copies for Shared Folders (SCSF) allows end users
to use the “Previous Versions” UI to restore deleted or
overwritten files (or whole folders of files) without the need
for system administrator intervention. The process of creating
Shadow Copies does not affect the way that users work, since
the process is transparent to users. However, should a file be
deleted or overwritten, the user is empowered to manage their
own files, recovering lost data and fixing mistakes without
having to rebuild the file or wait for IT to restore it from tape.
Restored files retain the permissions and file preferences
associated with the original files. Moreover, since SCSF
works with any type of file built with any application, all
users can benefit.
Data Transport
Using third-party software, shadow copies can be made
available to other servers that share a common storage pool.
Transport of data among systems is virtual, and is done
through the process of LUN masking and unmasking, under
VDS control. Virtual transport of data enables servers to share
data for more effective backups, data mining and testing.
Data Protection
User-enabled Shadow Copies for Shared Folder (SCFC) file restores
Open-file backups
System
Management
With third-party support, shadow copies can be transported to other systems for backups, data mining or testing
Faster backups
Faster restores
Cost Control Fewer staffing resources needed
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The FRS is used to copy and maintain files and shared
folders on multiple servers simultaneously. When changes
occur, local site content is synchronised immediately; remote
site content is changed according to an administrator set
schedule. FRS, in conjunction with DFS, makes data highly
available, even to remote sites.
It is important to note that FRS is not an effective means
of providing data protection from software bugs, viruses or
other causes of data corruption, since the corrupted data is
replicated to failover disks as well.
DFS for File SharingDistributed File Sharing (DFS) is enhanced in
Windows Server 2003 and Windows Storage Server 2003.
DFS enables storage solutions that are:
DFS simplifies locating and managing data multiple network
servers. This is especially important to users who must get
access to widely distributed data on different servers, but
do not want to be hampered with having to remember and
provide the server address that data lies on in order to
access it.
Unified Namespace
The DFS enables end users to readily find data housed
on different disks by presenting a single view of physical
storage, as if the data were only on a single machine. The
system administrator accomplishes this by set up a single
unified system of naming (the “namespace”) such that users
FRS for Remote Replication File Replication Service (FRS) is enhanced in
Windows Server 2003 and Windows Storage Server 2003.
FRS enables:
Highly Available Data Failover to replicated disk in the event of hardware failure
Scalable
Enables consolidation of distributed shared folders into a single namespace
Simple integration of new servers and storage into namespace
Manageable Users can readily locate and share data
Fault tolerant Microsoft® Active Directory® information is used to provide failover to alternate site
Highly Available Load balancing helps keep user files highly available
Cost-effective Failover to least expensive alternate site
can share and access files, whether they are on the same
machine, in different departments, or at branches of an
organisation across a country.
Simple Migration
As organisations move existing data to newer, more powerful
servers, the namespace organisation remains the same,
without requiring additional user education.
DFS has been enhanced by directing clients to the closest
available DFS server, rather than having them accessing a
distant share if one is available nearby or even locally. Not
only does this help businesses control costs, it also ensures
the best network performance for each client.
While backing up data to tape protects mission-critical data
from catastrophic events such as fire or massive electrical
surges, it does nothing to protect system software stored on
the hard drive, since that information is not copied during the
backup process. A critically damaged hard drive will lose all
critical registry information, system files, and disk partition
information; nothing remains but the bare metal. Restoring
the base operating system plus the backup application (the
minimum required to restore backed up applications and
data) is a time-intensive process.
With ASR, the system administrator prepares for such a
disaster by saving to floppy disk a complete backup set of
information about how the server was configured, including
any volume information. In the event of system failure, this
backup set is used with the ASR restore CD (which contains
the necessary software and drivers to allow the restore) to
rapidly restore all system setup information.
ASR is also useful when upgrading to a more powerful server,
since it eases the process of migrating system information
from the old server to the new.
ASR for Rapid Disaster Recovery Automated System Recovery (ASR) is new to
Windows Server 2003 and Windows Storage Server 2003.
ASR enables effective:
Disaster Recovery Allows complete recovery of OS and system settings
EFS encrypts data as it is stored to disk, preventing it from
being accessed or read by users who lack the appropriate
authorisation. The user may enable encryption without any
administrative intervention. Backup copies of encrypted files
are also encrypted. To encrypt data traveling over the network,
Internet Protocol security (IPsec) is also available. Encryption
is especially useful for mobile units that are highly vulnerable
to theft.
EFS has been enhanced to prevent the removal and mounting
of storage volumes onto a different system. In Windows
2000, because encryption had been enforced at the file and
directory level, security protection could be bypassed.
In Windows Server 2003 and Windows Storage Server 2003,
the data itself is encoded, preventing such security breeches.
Administrators can authorise additional users to access
encrypted files, as well as enable users to encrypt Web
folders, thus provide a simple and highly secure method
for users to share folders.
EFS for Secure Data Encrypted File System (EFS) is enhanced in
Windows Server 2003 and Windows Storage Server 2003.
EFS enables effective:
Data Protection Data protected even on mobile units
1211
Conventional networking technology enables network file
transfer. However, for some applications (such as databases),
it is more effective to transfer data to storage in its more
granular form of blocks rather than files. While parallel SCSI
interconnects enable transfer of block level data, both the
number of storage devices that can connect to a computer,
and the distance those devices can be from the computer,
are highly restricted. Fibre Channel (FC) uses the serial SCSI
protocol that enables block transport, and FC interconnects
facilitate the attachment of many devices over long distances
(10km at 1Gbs in standard implementations). Both these
factors have combined to make FC the dominant technology
for SAN solutions.
The following are disadvantages of FC:
The infrastructure (wiring, interconnects, switches and so
on) tends to run on proprietary firmware.
Specialised training (which is difficult to obtain) is
necessary for effective SAN management.
FC imposes a 10km distance limitation on data transfer;
iSCSI, on the other hand, enables data transfers over WAN
distances.
The development of iSCSI – block-based storage over
IP networks – is a technological breakthrough that can
leverage a company’s existing infrastructure to provide a
SAN solution. Microsoft’s iSCSI initiator enables computers
to access storage on the network, to determine if the storage
is available for use, and to transport data securely over the
Internet to the storage device. Microsoft’s iSCSI initiator,
available for free and downloadable from the Internet,
helps bring high-end solutions – like SAN – to mid- and
small-sized businesses.
iSCSI for Storage Area Networking Internet SCSI (iSCSI) is new to Windows Server 2003 and
Windows Storage Server 2003.
iSCSI provides storage solutions that are:
Scalable Enables block-based (SAN) storage on existing IP networks
Manageable Leverages existing networking technologies
Cost-effective
Dedicated Fibre Channel (FC) equipment unnecessary
No specialised training required
MPIO for Highly Available Data Multipath Input/Output (MPIO) is new to
Windows Server 2003 and Windows Storage Server 2003.
Multipath I/O provides:
MPIO, multipathing or redundant paths for I/O channels,
provides an alternative connection to the storage devices
in case of failure of the primary I/O path. Optimally, MPIO
can provide multiple paths (up to 32) to stored data in
order to improve performance through load balancing.
Path redundancy has long been critical to enterprise
scale organisations.
Microsoft’s MPIO solution is only available though the Driver
Development Kit (DDK), which allows storage vendors to
create interoperable multipathing solutions in their hardware
products. System administrators and end users benefit from
using these products, since they help ensure that end users
have highly available data even in the event of a failure of a
component in the path between the client and storage.
Users can also benefit from increased performance.
Enhanced Support for SANsWith the appropriate interconnect technology (iSCSI or FC),
deploying a SAN in a Windows environment is much simpler
using Windows Server 2003 operating system than it had
been for previous versions of Windows.
Ability to boot from the SAN. Previous versions of the
Windows platform required that the boot operation be
conducted using the storage attached to the main server.
If that server failed, however, another server had to reboot
the system, which could be a time-consuming and difficult
process. In combination with SAN vendor support,
the Windows Server 2003 operating system enables
the system administrator to reboot across the SAN,
thus reducing downtime.
Flexible Volume Mounting. In the past, in the shared
disk environment of SANs, if Windows was able to detect
a virtual disk, it would attempt to claim it for its own,
failing to recognise another system’s prior ownership.
This limitation could result in loss of data. By controlling
mount points, Windows is prevented from accessing
volumes that are not assigned to the OS.
Highly Available Data Failover to an alternative path in case of path failure
Fault Tolerance Redundant hardware enables failover
1413
Companies of all sizes are searching for cost-effective
solutions to their storage management challenges. Many of
the high-end storage solutions – including the consolidated
storage network model itself – were first worked out to solve
the business problems of large companies. These storage
customers have demanded the most advanced technologies
available to solve their storage problems, and have driven the
development of many technological innovations.
Windows Server 2003 and Windows Storage Server 2003,
together with Microsoft’s OEM and Independent Software
Vendor partners, deliver advanced storage management
solutions to a diversity of companies. Snapshots and remote
replication capabilities are no longer the exclusive tool set of
high-end (and high-priced) storage solutions. These powerful
capabilities are built into Windows Server 2003 and
Windows Storage Server 2003, making advanced storage
solutions available to mid-sized and even small organisations.
Microsoft also provides advanced storage solutions to
enterprise organisations. For many years, large companies
had been locked into using a single hardware or software
provider for all of their storage needs, regardless of the
fact that not all needs required enterprise-level solutions.
As greater interoperability becomes part of the storage
standard, lower-cost options from multiple vendor sources
are possible. Microsoft’s robust storage platforms provide
one such option.
SummaryIntroductionDevelopment of technologies delivering storage over the
network has revolutionised the availability, distribution and
accessibility of storage resources. Attaching storage directly
to the company network helps to eliminate or reduce the
drawbacks that businesses experience when using DAS.
These drawbacks include:
Limited storage capacity and scaling constraints as data
assets grow.
Proliferation of computer hardware and software to meet
increased storage capacity needs.
Proliferation of hardware and software necessary to protect
the data allocated to new storage.
Increased management complexity for the system
administrator(s) configuring and maintaining IT client and
server systems.
Poor or inconsistent protection of data on client desktops
and laptops.
Limited or laborious access to data, especially between
company workgroups, departments and branches.
Temporary or permanent loss of data resulting from
hardware failures, data corruption or user error.
Spiralling costs associated with capital expenditure,
increased staffing, and production downtime resulting from
data loss.
Network Attached Storage (NAS) is one solution to these
challenges. NAS storage and file-serving devices can be
attached directly to the company intranet. Storage directly
attached to the network becomes accessible to all computers
that can access the network. NAS servers are designed
for ease of deployment: they can be plugged directly into
the network without disruption of services, management is
minimal and simplified, and they are largely maintenance
free. NAS devices are an ideal means by which to consolidate
file servers and backup equipment and to expand
storage capacity.
A second networked storage solution is the installation of a
SAN. Unlike NAS solutions, these dedicated storage networks
require considerably more planning to deploy, and their
management is more complex. SAN solutions are ideal for
database and online processing applications requiring rapid
data access, but because SAN storage devices serve block-
level data rather than files, the installation of a Fibre Channel
(FC) network to transport the SCSI (Small Computer System
Interface) commands is necessary4.
A third storage network solution is a hybrid one: NAS devices
can be attached to SANs. In this configuration, the NAS
components necessary for filing are physically separated
from the components necessary for storing: a NAS “head” or
“gateway” (containing the filing functionality) attaches to the
LAN network, and behind that lies the storage component
– a SAN consisting of the FC network (wiring and switches)
and the storage disks.
Overview of Windows Storage Server 2003
1615
4 Microsoft, with its iSCSI initiator software released in June 2003, is enabling block transport over company intranets. See the Enterprise Storage Division white paper, “Microsoft Support for iSCSI” for details.
5 Any system designed to run an operating system.
What is Windows Storage Server 2003? Microsoft Windows Storage Server 2003 is a Network
Attached Storage (NAS) operating system that enables
OEMs to build appliances that provide dedicated file
serving capabilities and storage on the network. Windows
Storage Server 2003 is built on top of Microsoft Windows
Server 2003, which ensures that NAS devices built upon
the Windows Storage Server operating system have all
the performance and scalability benefits associated with
Windows Server 2003.
A NAS appliance built Windows Storage Server 2003 is
designed to perform without requiring a monitor, keyboard
and mouse. Instead, this “headless” appliance is managed
remotely through a Web-based user interface for the minimal
configuration tasks required for setup. Unlike application
servers that require proper planning to implement well, NAS
devices built with Windows Storage Server 2003 are designed
to be deployed in under 15 minutes, and can be attached
directly to the company Local Area Network (LAN) with no
interruption to services. Once plugged in, these NAS devices
require minimal maintenance.
Unlike proprietary solutions, Windows Storage Server 2003
works with standard hardware5 from multiple OEMs. This
gives businesses maximum flexibility in choosing among
vendors with the hardware solution that best meets
their needs.
Advantages of Windows Storage Server 2003Windows Storage Server 2003 is designed for simplicity,
reliability and performance. NAS appliances built on Windows
Storage Server operating system integrate seamlessly into
the IT network to provide one of the most economical file
serving and NAS solutions available to departmental and
enterprise-sized businesses.
Ease of Deployment. Depending on the expertise of the
system administrator and the complexity of the computing
environment, installation of an application or general
purpose server can take anywhere from several hours to
a day or more of work. Because Windows Storage Server
2003 comes preconfigured, other than using the Web
browser interface to set up users and shares, the only
installation work necessary is plugging the device into the
company LAN. In under 15 minutes, gigabytes to terabytes
of storage can be made available to users across multiple
OS platforms.
Simple Management. Windows Storage Server 2003 can
be managed remotely though Terminal Services sessions
or through a Web browser interface from any desktop on
the network. Because Windows Storage Server 2003 uses
the Windows operating system, administrators already
familiar with Windows do not have to learn a new NAS
operating system.
Dependability. Windows Storage Server 2003 is designed
to fully support redundant hardware components – disks,
power supplies and fans – to provide continuous and
uninterrupted availability should a hardware failure occur.
And because NAS devices are designed this way, the
potential points of hardware failure are fewer than with
general-purpose servers.
Enhanced Data Protection. Through built-in point-in-
time shadow technology, Windows Storage Server
2003 helps businesses keep their data online 24 hours
a day, 7 days a week. Using the infrastructure provided by
Windows Server 2003 VSS, the system administrator can
use point-in-time shadow copy technologies to make up to
512 snapshots per volume using NTBACKUP (of which
64 are reserved for Shadow Copies for Shared Folders).
These Shadow Copy backups are available for rapid
restores should the need arise. Unlike tape backups,
which can take hours to restore, these Shadow Copy
backups can be restored in minutes.
The end user can also benefit from point-in-time imaging
technologies, using the Shadow Copies for Shared Folders
(SCSF) feature. SCSF enables users to restore accidentally
deleted or overwritten files or entire folders without the need
for IT intervention. A maximum of 64 SCSF per volume
can be created.
ISV Utility Support. NAS devices developed with
Windows Storage Server 2003 include all of the benefits
of application support available in Windows Server 2003.
Critical ISV utilities, such as antivirus, backup, replication
and disk quota software, are immediately available and
supported in Windows Storage Server 2003. NAS devices
not based on Windows Storage Server 2003 are not able to
support these kinds of products without special versions,
or those operational procedures must be performed from
application servers on the NAS files and file.
Robust Security. Because it can be integrated seamlessly
with Microsoft® Active Directory® services, Windows
Storage Server 2003 can take advantage of the Windows
security features such as data and file encryption, network
authentication, secure network transport, and network-
wide group policies.
Load Balancing and Server Failover. Windows Storage
Server 2003 integrates effectively with the Distributed
File System (DFS), enabling effective management of the
servers and files on the business network. DFS works to
provide a single hierarchical view of all the servers and
their shares. Replicating the data across multiple servers
and keeping the data synchronised with File Replication
Service (FRS) is an effective way to balance the network
load. In the event that a server fails, DFS will automatically
redirect clients to the closest available server.
1817
This section provides a brief introduction to how the NAS
server works, and is included to help provide the context for
many of the NAS features available with Windows Storage
Server 2003. Like all NAS servers, Windows Storage
Server 2003 functionally and architecturally consists of
three components: the filing system, the wiring (and related
hardware), and the storage (disk6). These components
together provide the functionality necessary to fulfil
client system application requests for data stored on
the NAS device.
Application requests to read or write data are initiated by
the client system, and can be directed to the storage local to
the client (embedded or DAS), or can be redirected over the
network to the NAS device using network transport protocols.
These I/O requests are then processed by the NAS operating
system before being passed to the disk devices for storage.
File-Serving ComponentThe process of storing and retrieving the data requested by
user applications is known as file serving. File serving is under
control of the operating system software.
1. Application I/O requests (to read or write data) flow from
client-side applications over the LAN to the NAS operating
system (kernel), which queues and schedules the various
client application requests. These requests then pass
to the file system and the volume manager of the
operating system.
2. The file system portion of the operating system controls
security and determines whether or not a file can be
created, opened, written to. The file system also ensures
that the file is addressed to the correct storage destination.
The I/O request then passes from the file system through
the Volume Shadow Copy Service layer (where it may or
may not be processed) volume manager.
3. The volume manager portion of the operating system
readies the data for the specific device(s) it will be
passed onto for storage7. The Virtual Disk Service
(see later section in this paper) is a component of the
volume manager (but not a component of I/O requests).
Hardware ComponentHaving passed out of the operating system, the I/O request
travels over the host bus to the host I/O controller, which is
responsible for correctly addressing the appropriate storage
device and correctly transferring the I/O request commands
and data across the storage I/O bus to the storage device.
Storing ComponentHaving passed into the storage device, the application request
(data) is stored on the appropriate physical or logical disk, as
directed by the file system.
Optimising NASVendors can configure NAS hardware (and firmware8) such
that it is optimised for network file I/O processing and storage.
These components include the NAS processor, memory and
caching, and the storage devices. There are many different
ways to optimise file serving, and the particular approaches
taken are vendor-specific.
The next section describes the networking, file serving and
storage features in Windows Storage Server 2003 that drive
these capabilities.
The Basics: How NAS Works
6 Disks can be both physical and logical (virtual).
7 It is at this step that the data associated with the application request is converted from file format into the constituent granular blocks that are written to storage devices.
8 Software on the vendor hardware; not part of the OS.
This section highlights the networking, file serving and storing
capabilities of Windows Storage Server 2003. This section
provides feature highlights. For a summary of the major
advances in Windows Storage Server 2003, see
“Key Improvements Since Windows Powered NAS 2.0”.
Networking Network Data Transmission Protocols
In order for clients to access storage on the NAS device, they
must be connected to the LAN and network transport must be
enabled. Clients most commonly connect to the NAS server
over Ethernet cabling using the TCP/IP protocol. Depending
on the system platform, other protocol layers may also be
necessary for network transport. Windows Storage Server
Windows Storage Server 2003 Features 2003 provides support for network protocols used by not only
Windows systems, but also by UNIX and Apple systems (see
Table 1), enabling networking across multiple platforms.
Network Security
Windows Storage Server 2003 uses the authentication
services of Windows Server 2003 to ensure that only those
users with permission to access data can do so. An additional
layer of protection is available through the data encryption
capabilities of the Windows operating system (See Table 2).
The NAS Windows Storage Server is able to support security
features for UNIX and Macintosh environments, as well as
earlier Windows platforms.
Network Protocols Additional Information
TCP/IP Used to connect hosts to the Internet.
AppleTalk Networking protocol for Apple computers.
IPX Internet packet exchange. (Administration through Remote Desktop.)
NetBEUI NetBIOS Extended User Interface, used for Windows environments.
SNMP Simple Network Management Protocol, Internet standard for network management.
Telnet Provides remote terminal access to host.
Fibre Channel Transmits block-level data; most common in SAN configurations.
Ethernet Physical network, transmits files; most common transport for NAS.
Table 1. Networking Protocols Supported by Windows Storage Server 2003
Security and Authentication Additional Information
Kerberos Network authentication protocol for client server configurations.
SSL Secure Socket Layer protocol, provides connection security for Web servers.
IPsec Internet Protocol Security, provides encryption for network transmission.
Active Directory Directory service for Windows OS, acts as central authority for network security.
Windows NT® DomainAdministration (including security and authentication) of users, groups, servers and so on in Windows NT environments.
NTLM Windows NT LAN Manager provides security for connections between NT clients and servers.
NIS Network Information System (for UNIX servers).
Apple UAM User Authentication Module.
Table 2. Security and Authentication Support in Windows Storage Server 2003.
2019
File ServingFile Sharing Protocols
File serving, as discussed earlier, is the process of opening,
closing, reading and writing files. In order for file serving to
be enabled over the network, file-sharing protocols must be
supported. These protocols enable clients to make requests
and receive responses from remote devices, such as a NAS
storage box.
Many NAS devices enable only simple file processing
because they include support only for the standard file
systems: the Common Internet File System (CIFS) and
Network File System (NFS). In contrast, Windows Storage
Server 2003, with its support for multiple file sharing
protocols (Table 3), allows for complex multi-platform file
processing. In addition to Windows clients, Windows Storage
Server 2003 supports file processing for UNIX, Macintosh,
and Web HTTP clients, among others.
Supported Utilities and Applications
Although one of the advantages of NAS is that it is a
dedicated file server and not overburdened with applications,
the data on the server nevertheless requires protection
from data corruption, and the possibility of hardware failure.
Because it is based on the Windows Server 2003 operating
system, Windows Storage Server 2003 is able to support
anti-virus and backup utilities (see table 4). In addition,
Windows Storage Server 2003 integrates seamlessly with
critical Windows features, such as DFS and FRS.
Protocols Additional Information
SMB/CIFS Enables Windows system-based file sharing.
NFS Enables UNIX/Linux-based file sharing. NFS 3.0 supported in Windows Storage Server 2003.
AppleTalk Enables Apple file sharing.
HTTP Enables Web file sharing.
WebDAV Enables desktop users to manage Web-based files using HTTP.
NetWareEnables Novell-based file sharing. Administration through Remote Desktop.
Table 3. File-Sharing Protocols Supported in Windows Storage Server 2003
Software Support Additional Information
Anti-virus Via third-party software.
Backup Via third-party software. Includes the backup utility NTBACKUP that uses VSS and SCSF to back up both system and user data withShadow Copies.
Distributed File System (DFS) Enables a single hierarchical mapping of all systems and shares on the network.
File Replication Service (FRS)Enables remote mirroring through replication.Synchronises data9.
Internet Information Services (IIS)Tool to host and manage Web pages on intranet or Internet. Version 6.0 supported in Windows Storage Server 2003.
Table 4. Software Supported in Windows Storage Server 2003
StorageManaging Storage Devices
Management and configuration of the storage disks
(both physical and logical) is under control of the VDS
(see “New Features” for more information).
Allocation of disk space to users is performed through
quotas, and can be managed through a user interface.
The Enterprise Edition of Windows Storage Server 2003
supports the Automated Deployment Service (ADS) as an
optional add-on. ADS is a scriptable service enabling
rapid and highly effective deployment of large numbers
of new servers.
Ensuring Availability of Stored Data
A number of existing technologies have been enhanced
and a number of new features have been added to
Windows Storage Server 2003 to help keep a business’s
data highly available. These technologies range from tools
to ensure hardware components are operating effectively
and at high performance, to technologies enabling
hardware (MPIO) and software (clustering) redundancy, to
data availability techniques for redundancy (VSS and RAID)
and high performance.
Disk Management Additional Information
Virtual Disk Service (VDS) Includes sample code for volume management.
Quota Management Enables administrators to limit the storage accessible by each user.
Automated Deployment Services
(ADS)
Enterprise Edition only. ADS enables administrators to perform script-based administration of large-scale deployments of Windows servers.ADS replaces Multi-Device Manager (MDM) in WP NAS 2.0.
Table 5. Disk and Deployment Management Capabilities in Windows Storage Server 2003
Reliability/Availability Additional Information
Volume Shadow Copy Service
(VSS)
Enables up to 512 point-in-time copies per volume, of which 64 are reserved for SCSF if enabled on the volume. This service replaces the Persistent Storage Manager (PSM) in WP NAS 2.0.
ClusteringProvides application failover. Windows Storage Server 2003 Enterprise Edition supports up to 8 nodes. (WP NAS 2.0 supports a maximum of 2 nodes.)
Software RAID 0, 1, 5RAID types provide differing levels of data protection and redundancy.VDS also enables hardware based RAID.
Multipath I/O (MPIO) Enables high performance and high availability through multiple paths to storage.
System MonitoringMonitors performance of the operating system. Allows system administrator to assess I/O performance with different devices.
Watchdog Timer Detects system hangs; can be programmed to reboot system after a given time.
Table 6. Features Enhancing System Reliability and Data Availability
2221
9 Web UI support for Distributed File System (DFS) does not include or enable FRS scenarios.
Key Improvements Since Windows Powered NAS 2.0Windows Storage Server 2003 has been improved in a
number of key areas relative to Windows Powered
NAS 2.0. This section highlights improvements in the key
areas of file serving performance, integrated snapshots,
and the user interface.
PerformanceAs a dedicated file server, the speed with which NAS boxes
can handle I/O read and write requests is a critical factor in
overall performance of systems on the network. Windows
system-based NAS boxes communicate with client systems
using the SMB (Server Messenger Block)10 or CIFS
(Common Internet File System) protocol for Windows systems.
For UNIX-based systems, the NFS (Network File System)
protocol is used.
SMB Performance
The industry standard in measuring SMB/CIFS file
server performance for Windows Clients is NetBenchTM
benchmarking software. File server performance is
measured as throughput (megabits per second) versus
number of clients.
Comparisons of Windows Storage Server 2003 and NAS 2.0
using the same hardware configurations directly capture
improvements in the Windows operating system performance.
These improvements stem from changes to the kernel
(improved caching, buffering, and the like), as well as changes
reflected in the use of SMB in 2003 versus CIFS in 2000.
Differences between studies capture differences attributable
to different hardware configurations.
In both internal Microsoft benchmarks using NetBench and a
commissioned third-party benchmark test, the performance
of Windows Storage Server 2003 is greatly enhanced
compared with NAS 2.0. In third-party Veritest comparison11
of file serving in Windows Storage Server 2003 and NAS 2.0,
peak throughput on Windows Storage Server 2003 is 35-85
percent faster than Windows Powered NAS 2.0, depending on
whether there are one, two, four or eight processors12 (See
Figure 1). Internal Microsoft tests, using a different hardware
configuration, put the overall throughput at 100 percent or
above for each of the four processor configurations.
NFS Performance
The industry standard for measuring NFS file server
performance for UNIX clients is based on the Spec SFS
benchmark program produced by the Standard Performance
Evaluation Corporation. Spec SFS scores file server
performance in terms of I/O Throughput Per Second
(IOPS). In internal MS tests13 using Spec SFS, file serving
performance increased from 5040 IOPS in NAS 2.0 to 7500
IOPS in Windows Storage Server 2003, a 50 percent increase.
NAS Management SoftwareDepending on the complexity of the deployment scenario, the
need for NAS management ranges from the minimal (plug
and play) to the considerably more complex (see Table 5).
Windows Storage Server 2003 provides a number of different
interfaces to meet such management needs, including both
local and Web-based UIs (see Table 7).
Management Additional Information
Web User Interface (UI)Enables administrators to manage users, create shares and control backups and similar tasks from any location on the network or Internet.
Remote Desktop Enables remote control of other systems for administration.
Table 7. Management Interfaces in Windows Storage Server 2003
Integrated Snapshots In NAS 2.0, point-in-time imaging (snapshot) technology is
available only through the integration of third-party advanced
backup software. In Windows Server 2003, snapshot
technology is part of the Volume Shadow Copy Service
(VSS) and is fully integrated into the operating system, thus
making it part of the Windows Storage Server 2003 package.
Snapshot technology enables open file backups and fast
restores. The technology is especially useful when the goal
is the restoration of individual files, which can be done by
the end user without the need for system administrator
intervention.
Improved End-User ExperienceWindows Storage Server 2003 has a number of enhanced
User Interfaces (UIs) for the end user and the system
administrator. On the client side, the Previous Versions
user interface (SCSF) allows end users to restore their own
files directly in the event of accidental deletion, overwriting
or file corruption. On the system administrator side, UIs for
volume defragmentation, task scheduling, folder and
share management, volume management, and UPS
management make administration of storage much
zmore convenient than before.
Figure 1. NetBench comparison of file-serving performance in NAS 2.0 (Windows 2000 Server) and Windows Storage Server 2003 (Windows Server 2003).
0
200
400
600
800
1000
1200
4P3P2P1P
Peak SMB Performance
Thro
ughp
ut (M
bps)
Windows 2000 Server Windows 2003 Server
2423
10 SMB Is Server 2003’s enhanced version of CIFS (native to Server 2000)
11 See the report at www.veritest.com/clients/reports/microsoft
12 It is important to note that these performance improvements are seen only when upgrade client software is loaded onto the client systems.
13 For configuration details, see Windows Storage Server 2003 OEM training guide.
The following are new features in Windows Storage
Server 2003.
Volume Shadow Copy Service
Virtual Disk Service
MPIO
DFS
Volume Shadow Copy Service (VSS)The VSS is an infrastructure that makes possible enhanced
data protection though high-fidelity backups, rapid data
restores, and data transport.
VSS is a component of the operating system and, as such,
is not accessed directly by users. Instead the VSS coordinates
with user applications, backup applications and storage
hardware to enable the creation of point-in-time Shadow
Copies of data on single or multiple volumes without
affecting performance significantly.
High-Fidelity Backups
Shadow copy creation is a highly effective means of protecting
data with several advantages over traditional tape backups
when the goal is not long-term archiving. Tape-based
technologies are time-intensive to run, impose a considerable
bandwidth burden on the local network, and can have data
inconsistency issues if applications are open during the
backup process. As a consequence, tape backups tend
to be scheduled relatively infrequently and at times when
applications are not in use (such as nights or weekends) – a
strategy that can work reasonably well for companies that do
not require 24x7 operations. In contrast, Shadow Copies can
be created in seconds, without the impact on network traffic
that tape backups impose. Additionally, because the Shadow
Copy process allows open files to be backed up without data
inconsistency issues, they can be scheduled at any time,
and much more frequently than tape backups.
Fast Restores
In the event of data loss, Shadow Copy restoration offers
significant advantage over tape restores. Because the
Shadow Copies can be saved on storage arrays on site, they
can be accessed directly, without the need to travel offsite
to a tape data vault, locate and bring back a tape. Even
more significantly, Shadow Copy restores take only minutes
to complete, while tape restores, depending on the type of
backup (full, differential or incremental) and the amount of
data, can take hours or even days to do correctly.
Shadow Copies for Share Folders
System administrators are not the only people to benefit
from the fast restore functionality enabled by VSS. System
administrators can activate SCSF, thereby enabling end users
who overwrite or accidentally delete a file to restore a previous
version of a file for themselves, rather than having to recreate
the file or request that a system administrator do a high-cost
single file restore from tape.
Shadow Copy Transport
All of the functionality discussed above is provided with the
in-box Shadow Copy technology on the operating system.
The exception to this is Shadow Copy transport among
systems – whether for backup, data mining, testing or fast
restores – that requires a hardware provider on the SAN.
In a DAS configuration, this data transport between servers
is physical. In a NAS-SAN configuration with pooled storage,
data on the SAN can be accessed (through masking and
unmasking) between servers. Although access to the storage
pool is shared, each server can only access the specific LUNs
(Logical Unit Number) assigned to it (since two servers cannot
both write to the same volume without potentially causing
data corruption). But using the hardware provider on the SAN,
a point-in-time Shadow Copy can be virtually “transported”
to another server for use, through the process of masking
and unmasking.
Windows Storage Server 2003 Features Virtual Disk Service (VDS)In order for a server to use new storage disks, they must first
be made accessible to the server and then formatted for use.
VDS controls the process of making storage accessible to
systems that need it. While it is irrelevant to application (or
the user) how the data is stored – whether it is on a single
physical disk or spanned across several disks (a logical unit),
in terms of data protection and performance, the impact of
how the data is stored is significant. Thus VDS can either
present a physical disk or a logical disk to a server.
Physical disks do not require the first two steps.
1. Create logical units; assign number IDs
(now referred to as LUNs).
2. Unmask LUNs to server.
3. Create partitions and volumes.
4. Format the file system.
Basic Disks. VDS is used to partition14 each physical
disk and to create the volumes that can be mapped to
drive letters for use. These volumes are known as “simple
volumes” and do not span multiple disks. Basic disks are
the legacy disks, predating Windows 2000 capabilities.
They do not offer the same performance and data
protection that dynamic disks offer.
Dynamic Disks. VDS can be employed to create dynamic
disks that can consist of either simple volumes or multi-
partition volumes15. Multi-partition volumes physically span
more than a single disk but, nevertheless, are logically
considered to be a single volume. Dynamic disks can be
spanned, striped (RAID-0), mirrored (RAID-1) or stripped
with parity (RAID-5), depending on the level of performance
and data protection desired. VDS can be used to expand
dynamic disks to make more space available to a volume.
Although many vendors provide NAS appliances preconfigured
with RAID, system administrators might want to use VDS to
customise the storage solution to meet specific data storage
needs, whether relating to capacity, performance or data
protection.
VDS can also be used to attach a NAS device to SAN. These
NAS “heads” contain only the file serving capabilities; for
highly scalable and highly available pooled storage, they
plug into a Fibre Channel SAN. Each storage unit on the SAN
must have its storage configured and made accessible to
the appropriate servers only. Since it is common for storage
on the SAN to be from multiple hardware vendors, prior to
Windows Server 2003 and Windows Storage Server 2003,
it was necessary for the system administrator to configure
each device using a vendor-specific storage management
application. Not only did this mean using hardware-specific
management utilities, it meant that, frequently, the system
administrator had to go physically to each storage device to
do each configuration.
The VDS of Windows Storage Server 2003 helps to alleviate
these administration complexities in a NAS SAN configuration
by providing a single management interface for multivendor
storage devices. The system administrator can manage all
storage devices directly from a single management console,
and query and configuration
operations are common across all managed devices.
In this scenario, VDS functionality is enabled through
hardware vendor support. Each hardware vendor must supply
a VDS “provider” for the storage hardware. The hardware
provider translates the VDS standard APIs (Application
Programming Interface) into instructions specific to the
storage device. With communication enabled between the
VDS and the storage hardware, the system administrator
can now use a single storage management interface to
communicate with multivendor storage devices.
Multipath I/O (MPIO)Multiple or redundant paths between storage devices and
the systems that use them enable persistent data availability
and high I/O performance. In essence, these technologies
provide for an alternative connection in case of failure of the
primary I/O path, and, optionally, multiple paths to improve
performance or balance loads.
MPIO software included in Windows Storage Server 2003
2625
14 Physical disks are divided into sectors; contiguous sectors are partitions. In the case of basic disks, the volumes are created within partitions, and are thus restrictedto a single disk.
15 Volumes can span one or more partitions on the same or multiple disks. Dynamic disk types include RAID configurations, and can offer better performance and reliability than basic disks.
is not a feature of the operating system, but is supported
through the Driver Development Kit (DDK). Multipathing
allows a host to have up to 32 paths to access an external
storage device, which facilitates failover and load balancing.
Multipathing technology is critical in ensuring highly available
data to businesses. In the past, multipathing was a solution
only available to large-scale enterprises; now this high-
availability solution is available to any organisation using only
Windows Storage Server 2003 (and Windows Server 2003)
technologies.
Microsoft’s MPIO delivers a standard and interoperable path
for communication between storage products and Windows
Server. With a platform upon which multiple third-party
storage systems can reliably interoperate, businesses have
greater choice when building a high-quality, highly available
network storage system, and system administrators will have
the flexibility to incorporate products from multiple vendors
into a single, interoperable and highly available storage
infrastructure.
Distributed File System (DFS)The DFS enables the system administrator to create single
hierarchical mapping of all systems and shares on the
network. By uniting files on different computers into a single
namespace, users do not have to sort through a network of
dozens of servers, each with their own separate directory
structure, but instead see the files as if they resided on a
single computer.
With the latest version of the server operating system, DFS
has been enhanced to allow multiple DFS roots on a single
server, thus reducing administrative and hardware costs
of managing multiple namespaces and multiple replicated
namespaces. In addition, DFS now delivers more reliable
load-balancing, better file replication between DFS sites and
servers, and closest-site selection for users accessing the
network. Closest-site selection ensures that in the event of
server failure or scheduled maintenance, users are routed
automatically to another server on the network that has a
replica of the data. For best performance and lowest cost,
clients are rerouted to the site closest to them.
NAS Deployment ScenariosThe following are common NAS deployment scenarios:
File Serving.
Server Consolidation.
Local and Remote Site Replication for Business Continuity.
NAS-SAN Fusion.
File ServingBusinesses need reliable file servers that can provide
highly available data at a reasonable cost. Off-the-shelf,
general-purpose servers are not typically configured with
fully redundant hardware components. Using a general-
purpose server for file serving and running applications can
compromise both tasks. In particular, file serving can be
negatively affected by the overhead associated with running
applications, as well as by the risks of system crashes
should an application fail. General-purpose servers have
the additional disadvantage of being platform specific,
necessitating a different file server to serve clients on
different platforms.
In contrast, NAS filers confer a number of advantages. NAS
appliances are designed for high reliability: they are built with
redundant disks, NICs (for failover data paths), and power
supplies. This redundancy of hardware components makes
NAS devices highly reliable file servers helping to ensure
highly available data.
Because NAS devices built on Windows Storage Server
2003 are dedicated file servers, they do not carry application
overhead, and they are not vulnerable to application-related
problems. Moreover, because Windows Storage Server 2003
supports multiple file sharing protocols, file serving to clients
on Windows, UNIX or Macintosh computers, and sharing
between them, can be accomplished without the need for
a specialised file server for each platform.
Server ConsolidationAs companies add more and more servers to meet demands
for increased storage capacity, equipment, licensing,
maintenance (power, space, servicing) and management
costs all escalate.
Adding a device based on Windows Storage Server 2003
to the network allows businesses to consolidate multiple
file servers into a single more powerful NAS device. Given
the broad file serving capabilities of Windows Storage
Server 2003, even file servers running on different platforms
(such as UNIX or Novell) can be consolidated onto one NAS
Figure 4. File serving between network clients and Windows Storage Server 2003.
WindowsStorage Server
2003
ClientsServers
Corporate LAN
Figure 5. Consolidation of several multiplatform servers onto a single Windows Storage Server 2003 NAS device. This scenario enables the consolidation of tape drives inot a single tape tray.
WindowsCorporate LAN
ClientsUnix
Windows Storage Server 2003
Consolidate Multiple File Servers onto
Windows Storage Server 2003
Corporate LAN
Clients
2827
Figure 6. Replication of data between NAS Windows Storage Server 2003 devices deployed at different branch sites.
Figure 7. Windows Storage Server 2003 (NAS “head”) integrated into Storage Area Network. Note Unix – change to UNIX
Windows
Corporate LAN
Corporate SAN with Shared Disk
Clients
Unix
WindowsStorage Server
2003
Switch
device, greatly simplifying management across systems.
Related equipment, such as backup devices, can also be
consolidated. System management is much simpler with
fewer devices requiring space, servicing (such as applying
patches or maintaining versioning), and backup and restore
services. For every NAS device replacing multiple existing
servers16, the associated licensing costs are eliminated.
Local and Remote Site Replication for Business Continuity NAS servers using Windows Storage Server 2003 software
technologies enable businesses to build fault-tolerant
solutions designed to keep data highly available.
NAS devices on a LAN can use the replication technologies
to replicate data between one NAS device and another. In
the event of network failure or the outage of a NAS device,
a second NAS device can assume the identity of a non-
functioning filer and continue serving files to clients without
interruption of services. When the non-functioning NAS device
returns, it takes back its identity, resynchronises its data with
the active NAS device, and resumes file serving.
This process of replication and failover also works on a Wide
Area Network (WAN). Replication and synchronisation occurs
over the WAN between NAS devices. Should one branch site
succumb to disaster or be shut down for a planned outage,
clients accessing that NAS device are redirected to a second
NAS device at a different branch.
NAS devices are also useful to remote sites for a different
reason. Branch offices often do not have the IT staffing
expertise to deploy general-purpose servers effectively.
Because they are so simple to deploy and maintain, NAS
file servers are the perfect plug-and-play solution for these
remote sites.
NAS-SAN FusionNAS devices can be integrated seamlessly into a SAN,
providing clients access to unlimited storage. In this
configuration, NAS storage is separated from the NAS filing
function and placed on the SAN. The NAS head now acts as
a gateway to the SAN, controlling distribution of the data over
the network and providing clients with maximum scalability
and high-performance storage solutions.
NAS-SAN fusion also enables system administrators to
move NAS backups off the LAN onto the storage network for
highly efficient and extremely fast backups that do not affect
LAN performance.
Windows Storage Server 2003 provides scalable, high-
performance storage solutions to businesses of all sizes.
Built on the Windows Server 2003 operating system, this
successor to Windows Powered NAS broadens usability and
interoperability for both end users and system administrators.
Using Shadow Copies for Shared Folders, end users are
empowered to recover their own lost data without IT
intervention, thereby improving their own efficiencies and
helping the business save money. System administrators
benefit from the seamless integration of Windows Storage
Server 2003 into existing networks, multiplatform file-serving
capabilities, and built-in point-in-time imaging capabilities for
highly efficient backup and restores.
Summary
See the following resources for further information:
Microsoft Windows Network Attached Storage Home
www.microsoft.com/windows/storage/default.mspx
Technical Overview of Windows Server 2003 Storage Management
www.microsoft.com/windowsserver2003/techinfo/overview/storage.mspx
Windows Server 2003 Storage Services
www.microsoft.com/windowsserver2003/technologies/storage/default.mspx
Windows Server 2003 File Server, Web Server, and Active Directory Performance Testing (4/03)
www.veritest.com/clients/reports/microsoft
Microsoft Windows Server 2003 versus Linux Competitive File Server Performance Comparison (4/03)
www.veritest.com/clients/reports/microsoft
Related Links
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16 The number of servers that can be consolidated on NAS device depends how powerful the server capabilities are and how many clients are served. Microsoft tests have demonstrated that up to 25 Windows NT servers can be consolidated into a single NAS device
ServersCorporate LAN
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