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Prepared for:

StrategicCommunications

Analysis:

Simplifying SAN administrationthrough host-based wizards

Analysis:

Author: Jack Fegreus, Ph.D.Technology Director

Strategic CommunicationsMarch 30, 2004

Prepared for QLogic Corp.

Jack Fegreus is Technology Director at Strategic Communications, which con-sults with a number of independent publications. He currently serves asEditorial Director of Open magazine, Labs Director of HP World and con-tributes to InfoStor. He has served as Editor in Chief of Data Storage,BackOffice CTO, Client/Server Today, and Digital Review. Previously Jackserved as a consultant to Demax Software and was IT Director at Riley StokerCorp. Jack holds a Ph.D. in Mathematics and worked on the application ofcomputers to symbolic logic.

Table of Contents

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Executive Summary 04

Assessment Scenario 06

The Out-of-Box Experience 07

SAN Lifecycle Management 11

Conclusions 14 03

Technology innovations, along with a new demand-driven consumer mar-ket, have radically changed the way large enterprises architect IT operations.These drivers are now emerging as powerful forces for change in the small-to medium-sized business (SMB) arena. Key drivers for change are:

•• Rise of the web as a 24x7x365 transactional environment

•• Use of customer relationship management (CRM) software totrack and direct sales efforts

•• Emergence of high-end, rack-mounted servers dedicated to single-task functions

•• Growing awareness at the corporate-officer level of the value of com-pany data and risks posed by backup and security vulnerabilities

To meet the imperatives of this new business environment, IT depart-ments in SMB enterprises are frequently structuring their IT servicesaround three to four servers dedicated to single strategic tasks:

•• A Windows® domain controller to provide file, print, and singlelogin services for desktop and laptop PCs

•• A Linux web server

•• An email server

•• A database server

Out of this new IT environment, the dominant cost driver has becomedata storage. While the capacity of disk drives has increased exponentially,the traditional method of employing dedicated SCSI-based storagedevices on each host along with the need to provide enhanced data securi-ty have weighed against any savings and have actually driven costs steadilyupward.

The reason for the escalation in storage cost-centers is IT’s near-religioususe of RAID arrays to provide servers with added data security. While

Executive Summary

EExxeeccuuttiivvee SSuummmmaarryy“What changes the equation in favor of SAN deployment at SMBsites is the introduction of technology that simplifies the deploy-ment and management of a SAN throughout its entire life cycle.”

04

RAID arrays do provide mathematical assurance in eliminating singlepoints of failure, RAID schemes require multiple drives, hot-spare drives,and in some cases duplicate drives for mirror sets. In addition, most sitesimplement RAID functionality through dedicated, expensive RAID con-trollers that incorporate on-board cache and battery backup. In such anenvironment, large-capacity drives become a source of overcapacity ratherthan a source of savings.

At large enterprise sites where total disk capacity is measured in tens, ifnot hundreds, of terabytes, the storage savings potential also totaled uporders of magnitude greater than SMB sites. As a result, the notion of vir-tualizing physical disk storage over a fiber optic network, dubbed a stor-age area network or SAN, proved particularly appealing much earlier.While the costs and complexity of early SANs were staggering, the sheervolume of storage in use at these sites made it financially attractive to be aSAN pioneer.

The generation gap between today’s SAN technology and the first-gener-ation SANs of the large enterprise data center is huge. SMBs can now takeadvantage of unprecedented innovation and affordability. The introduc-tion of low-cost disk drives, with capacities of around200 GB, makes itvery easy to build a 1-TB RAID array. While only a few of today's SMBservers require 1TB of storage, many SMBs are finding that their overallstorage needs are rapidly approaching the multiple-terabyte level.

While large-capacity drives provide an opportunity for cost savings, theydon’t always mean lower total cost of ownership (TCO). The costs associ-ated with configuration and maintenance of traditional SAN topologiesmakes it nearly impossible for a minimally-staffed IT organization to real-ize any operational savings. And some SMB environments will never growto use all the utilization capacity of the larger drives in a SAN installation.

What changes the equation in favor of SAN deployment at SMB sites isthe introduction of technologies that simplify the deployment and man-agement of a SAN throughout its entire lifecycle. To this end, QLogic®Corporation commissioned Strategic Communications to assess the newSAN technologies introduced with QLogic’s SANbox® 5200 stackableswitches. In this white paper, we examine the introduction of wizards inhost-based rather than device-based configuration software to simplifySAN installation and management.

Executive Summary

05

For this assessment, Strategic Communications examined the ease withwhich an initial working SAN fabric could be configured and then laterextended using QLogic SANbox 5200 switches and SANbox Manager™, ahost-based application program included with each switch. The targetuser was considered to be a seasoned systems administrator who had noprevious experience with SAN design or management. The target envi-ronment consisted of three servers running Windows Server™ 2003 andLinux that would access logical disk drive partitions from a central RAIDstorage system, as well as a central shared tape drive. The business con-straint for our test SMB site was the need to provide guaranteed 24x7x365access for all systems.

In particular, we set up a test environment using three Intel® Xeon™-based servers sporting PCI-X expansion slots. These servers came fromthree different manufacturers: a Dell PowerEdge™ 4400, an HP ProLiantML 350 G3, and an Appro 2400Xi. The Dell and HP servers were config-ured to run Windows Server 2003, while the Appro ran SUSE LINUXProfessional version 9.

Shared disk storage was handled by an nStor 4500F Series storage sys-tem. The system was populated with four IBM and four Seagate FibreChannel drives, which were formatted as two independent RAID 5 arrays,in order to provide approximately 1TB of total storage that would bedivided among the three servers. For robust performance and transparentfault-tolerance, the nStor 4500F system was set up with two RAID con-trollers in an active-active configuration. With a central storage systemconfigured in this manner, a seasoned system administrator can optimizeI/O across servers by assigning different primary controllers to differentarrays on different systems, while at the same time eliminating the possi-bility that a disk controller would be a single point of failure.

To complement the inherent fault tolerance provided by the active-activedual-controller configuration of our storage system, we chose to imple-ment a basic dual switch topology for our SAN fabric. Given the numberof devices being networked into our SMB SAN environment, a single 16-

Assessment Scenario

AAsssseessssmmeenntt SScceennaarriioo“We were able to go from boxed HBA and switch equipment to afully-functional, fault-tolerant working SAN in just 30 minutes.”

06

port SANbox 5200 would have been more than sufficient to support thecurrent structure and leave plenty of room for future expansion. A single-switch topology would, however, leave the switch as a single point of fail-ure and violate our business constraint to provide the most robust24x7x365 systems availability possible.

Needless to say, such robustness against device failure was not deemednecessary for shared tape drives. In fact, we deliberately chose an ExabyteMammoth2 drive with a 1Gb SAN interface in order to test the automaticspeed sensing function of ports on the QLogic SANbox 5200 switch.

The working assumption for our evaluation of the QLogic-based SANwas that all of this equipment would be in place and in working orderprior to the arrival of the SAN HBAs and switches from QLogic. Theoperating systems would be installed and running on the servers. Thefundamental RAID arrays on the shared storage system would be alreadyinitialized, which will take several hours with a terabyte or more of totalstorage capacity.

Given those constraints on our working test SMB environment, a keyevaluation criterion would be how quickly we could get our initial two-switch SAN fabric up and working. Remarkably, we were able to go fromboxed HBA and switch equipment to a fully-functional fault-tolerantworking SAN in just 30 minutes.

Opening the box containing a QLogic QLA234x HBA, system adminis-trators will discover a card included with the driver installation CD withinstructions to check the QLogic website for the latest drivers. In all likeli-hood, such a trip will be completely unnecessary. That’s because theQLogic drivers have been included in all of the latest operating systemdistributions. As a result, our most taxing moments installing the QLogicHBAs came when we needed to tell the Windows 2003 servers why wewere shutting them down.

Both Windows Server 2003 Server and SUSE LINUX Professional recog-

The Out-of-Box Experience

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TThhee OOuutt--ooff--BBooxx EExxppeerriieennccee“Adding an additional switch into a fabric built on stackable switches is just as easy as configuring the first switch.”

nized the new hardware and immediately installed the proper drivers.More importantly on the Linux side, the QLogic driver was recognized asa disk controller and not simply as a Fibre Channel interface. As a result,the QLogic drivers were automatically added to the initrd ram disk, whichis loaded at boot time. Unfortunately, this is not the case with all FibreChannel HBAs. Other HBAs will be recognized when the system is config-ured; however, they will not be automatically added into initrd, which willnot be automatically rebuilt. This task, which is rather trivial to do, mustbe performed manually by the system administrator.

While the task of manually rebuilding initrd is rather trivial, there is onerather serious problem: There is no warning that this task must be done.Worse yet, failure to carry out this task will cause the next system boot tofail if any SAN-based disk was left mounted at the time of shutdown.Without the driver loaded in initrd, Linux will not be able to see, let alonecheck, the file system on that drive.

Once the Fibre Channel HBAs are installed on the servers, the next stepis to configure the switches and create a SAN fabric. Upon opening up abox containing a QLogic SANbox 5200 switch, there is a software CDcontaining versions of SANbox Manager for Windows, Linux, and Solaris.Also included in the box is a folded sheet of paper entitled the "QuickStart Guide."

For anyone who has previously installed a SAN switch, an exceptionallyterse "Quick Start Guide" will likely cause some serious consternation.Starting with Step 5 (Apply Power to the Switch), moving to Step 6(Install SANbox Manager), and then followed by Step 7 (Run theConfiguration Wizard-after first connecting the switch to the Ethernet),we found the brevity of documentation disconcerting. There was not aword about configuring a serial port, launching Telnet, or running a com-plex menu-driven configuration program.

Not without some trepidation, we proceeded to follow the instructionsin the "Quick Start Guide." Not surprisingly, the installation of SANboxmanager on Windows Server 2003 Server was a trivial and near instanta-neous task. Quite surprisingly, the installation of SANbox Manager onSUSE LINUX was an equally instantaneous and trivial task. Marking thetime, we launched SANbox Manager on our SUSE LINUX server.


08

Immediately upon launching the wizard associated with configuring anew switch, it was clear that QLogic has concentrated on solving a lot ofthe annoying problems that plague systems administrators at SMB sites.For smaller sites, where the installation of new network devices is not afrequent occurrence, having to begin the set-up process via telnet over aserial connection is cumbersome at best, and for some, a daunting hurdle.

Thanks to some installation wizardry, there is no need for serial connec-tions or the specialized cables that such connections can require. Anadministrator simply plugs an Ethernet patch cord into the SANbox 5200switch and allows the network device discovery process to go to work. TheSANbox Manager wizard begins by asking for a temporary IP address thatit will assign the new switch during the configuration process. Once thataddress is entered, the wizard then requests that the administrator recyclepower on the target switch. The wizard then quickly discovers the power-cycled switch and puts it on the LAN using the given temporary address.

With LAN communications established, what follows is a simple seriesof configuration options for the switch:


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We began theprocess of configur-ing our first SANbox5200 switch in ourtest fabric via theSANbox Managerwizard at 2:01pm.

1. A SAN domain ID number2. A SAN symbolic name3. A permanent means for LAN address configuration4. The date and time for the switch5. A new password for the administrator

That's it! Within ten minutes of starting the process, we had configuredand were ready to commit our first fabric drive.

Normally, adding a second switch to a SAN fabric is a more complicatedtask than entering the first. An administrator must first decide how manyports on each switch will be dedicated to the creation of an inter-switchlink. Since each port on a switch is independently capable of deliveringdata at 2Gb per second to or from a device, two questions must beanswered:

1. How many ports on each switch might be communicating withports on the other switch at the same time?

2. How fast are the devices connected to each port?


10

Within ten minutesof starting the wiz-ard to configure aSAN switch, wewere ready to com-mit the switch profile.

Alternatively, a good rule of thumb is to dedicate four ports on each 16-port switch to provide a bandwidth of 8Gb per second for inter-switchtraffic.

Once the decision is made concerning the number of ports to divert tointer-switch traffic rather than to the task of connecting devices, anadministrator must then configure each of the ports on both switches tohandle their appropriate job. Most switches will automatically sense that aport is connected to a port on another switch and not a device. In suchcases, the switch will automatically configure such a port as an E-Typerather than an F-Type. Nonetheless, there is still more to the task thatmust be done manually. In order for the switch to load balance across anumber of independent E-Type connections, the corresponding ports oneach switch must be logically linked into a single trunk.

On the other hand, adding an additional switch into a fabric built onQLogic’s SANbox 5200 stackable switches is just as easy as configuring thefirst switch. Each QLogic stackable switch comes with four additional10Gb-per-second load-balanced ISL ports and a special cable to intercon-nect ISL ports between switches. By simply interconnecting two 10-GbISL ports on each switch with the cables provided with each SANbox 5200switch, our test SMB fabric had a completely configured 20Gb-per-secondtrunk without losing a single data port. We were then set to run the wiz-ard that would add the second switch and complete the fabric. Just 30minutes from starting with the installation of the QLogic HBAs, we wereready to start configuring SAN-based disks on our Windows and Linuxservers.

Getting a SAN fabric up and running is only a starting point. Far moreimportant for the long run is the ease with which a SAN can be moni-tored and maintained. Once again, the host-based SANbox Manager soft-ware that is included with QLogic SANbox switches far outstretches thecapabilities of switch-based web tools. In fact, for advanced device config-uration within our test SMB SAN environment, SANbox Manager provid-

SAN Lifecycle Management

SSAANN LLiiffeeccyyccllee MMaannaaggeemmeenntt“One of the most critical problems for a system administrator with-in a SAN environment is access control of devices.”

11

ed critical information needed to ease configuration of our nStor 4500Fstorage system that was not available from switch-based tools.

One of the most critical problems for a system administrator within aSAN environment is access control of devices. This is especially criticalwhen Windows servers are members of the SAN. The purpose of a SAN isto distribute logical SCSI devices to multiple systems. When the SCSI deviceis a tape drive and it appears on multiple systems, there is little cause forconcern, as the operating systems are well adept at detecting a busy tapedrive. Unfortunately, this is definitely not the case for a disk drive.

The first thing Windows wants to do upon discovering a new disk driveis write a signature on the drive. Linux is better behaved, but not all thatmuch. Without the addition of an external file system that can handleshared physical media, it is essential that logical disk units created on astorage system array be mapped in one-to-one fashion to a unique serverwithin the SAN fabric.

Such a one-to-one mapping can be configured using SANbox Managerto create soft/hard zones within the fabric based on any of the ports onany of the switches. By simply clicking on ports to create zones based oncollections of ports, the system administrator can limit which HBAs can


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Zoning of a SANfabric is simplifiedby SANboxManager's ability toreport on end-to-end devices withinthe topology.

discover/access devices. SANbox Manager’s ability to identify the devices,such as HBAs, RAID controllers, and tape drives that are connected toeach port greatly simplifies the zoning process. What’s more, the end-to-end reporting of SANbox Manager makes it much easier to use even morepowerful tools associated with SAN-attached devices.

As a case in point, nStor provides a host-based tool for managing nStorstorage systems dubbed StorView. Using StorView, a systems administra-tor can explicitly map logical disk drives partitioned from the physicalarray to any HBA connected to the fabric. Using the logical unit number(LUN) of a logical array and mapping it explicitly to an HBA is a highlyoptimal alternative to port-based zoning; however, to do this, an adminis-trator must be able to identify a server from the WWN code number ofthe HBA plugged into it.

One way to do this is to identify the switch port that is connected to theHBA with the particular WWN code. While QLogic’s host-based SANboxManager readily reports this information, many competitive switch-basedtools do not report it. Additional host-based fabric management softwaremust be purchased and installed to capture this data.


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By clicking on theName Server tab inthe topology view,an administratorcan get an end-to-end listing of alldevices in the SANfabric. Such areport is not oftenavailable fromswitch-based SANtools.

The combination of dedicated 10Gb-per-second ISL ports in theSANbox 5200 switches and SANbox Manager, a wizard-based host soft-ware package for SAN fabric management, provides a revolutionaryimprovement in the simplification of SAN implementation. By providinga hardware infrastructure and a software-monitoring tool that can enablean SMB site to bring up a SAN in 30 minutes, QLogic radically rational-izes the SAN as an attractive SMB storage approach.

Conclusions

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