achieving rapid data recovery for ibm aix environments - executive overview of double-take...

7/29/2019 Achieving Rapid Data Recovery for IBM AIX Environments - Executive Overview of Double-Take Availability for AIX

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Achieving Rapid Data

Recovery for IBM AIXEnvironmentsAn Executive Overview ofDouble-Take Availability for AIX


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W H I T E P A P E R

v i s i o n s o l u t i o n s . c o m2

Introduction

Planning for recovery is a requirement in businesses of all sizes. In implementing an

operational plan that ensures that both data and applications can be recovered, IT

personnel are generally confronted with several challenges:

How can I ensure my applications and data are recoverable without impacting

business operations?

Do I have data protection approaches available to me that meet my recovery point

and recovery time objectives?

Can I afford to implement a comprehensive plan that covers both my local and

remote (disaster) recovery requirements?

Are there cost-effective alternatives that meet my requirements?

Business requirements are not the only mandates that may be driving the evolution of

your recovery plan. Various industry-specic regulatory mandates, including Sarbanes-

Oxley, HIPAA and SEC, specify requirements for data retention and recoverability. In

meeting these requirements, businesses have to deal with a variety of risks to data:

inadvertently deleted les or records (operator error), viruses or hackers that can cause

data corruption or deletion, and natural disasters that may put much more than just

your data at risk. Distributed or branch ofces may also have ease of use requirements

that may not apply to larger, more centralized businesses.

Do you have a plan that meets your recovery requirements to your satisfaction across

these areas?


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Issues with Legacy Recovery Technologies

I youre like most Businesses, youre using some orm o data protection today probablytape-based backup. Periodically, someone shuts applications down to perorm a backup to

tape. Depending on the volume o data that is being copied, this may take several hours and

requires manual intervention to set up the backup job, run it, conrm that it occurred, and then

return the application to operation. The backup copy may be kept locally in case data needs to

be recovered in the near term, and eventually (ater several weeks) it may be moved to an osite

location or archival storage purposes. The reason to make and keep copies o your data is so

that, in the event o some sort o event or catastrophe that deletes or destroys data, you have a

clean copy saely tucked away to use or recovery purposes.

Tape is used or backup and archive because it is very inexpensive, but it is an old technology

that has been available almost since the dawn o computing. There are several issues with tape-

based backup:

Tape-based backup is a time-intensive process that is potentially disruptive to your

applications; this issue is commonly reerred to as the backup window problem.

Because of its impact on applications and resources, tape-based backups are usually not

taken more than once a day, and oten only once every several days, meaning that there

are very ew tape-based recovery points available or use over the course o a week; this

is problematic because your data is changing very requently (on the order o seconds or

minutes) and the ewer points in time you have a copy o (or recovery purposes) the more

data loss on average occurs or a given recovery; this issue is commonly reerred to as the

recovery point objective (RPO) problem.

Once it is clear that a recovery needs to occur, it takes time to perform the recovery (e.g.nding the right tape, transporting it (i its osite), restoring it to disk, restarting the application

on top o the data, etc.); this issue is commonly reerred to as the recovery time objective

(RTO) problem.

As a storage media for backup, tape is not entirely reliable; in fact, leading analyst groups

such as the Gartner Group, the Enterprise Strategy Group and the Taneja Group state that

as many as 1 in 4 backup tapes suer rom some sort o problem that precludes perorming

a recovery.

Transporting tapes to osite acilities or archival purposes also has inherent risk. Widely

publicized tape losses during physical transport (by truck) have hit large companies like Bank o

America, Citigroup Inc., ChoicePoint Inc. and LexisNexis and resulted in the theft of hundreds ofthousands o company records. Replication o data across secure IP-based networks is a much

aster, easier and saer way to transport data to osite locations or archival storage purposes.

I you are driven by either business or regulatory requirements to deploy a disaster recovery

solution, a pure tape-based data protection strategy can subject you to undue risk.

eading analyst groups, such

as the Gartner Group, the

nterprise Strategy Group and

e Taneja Group, state that as

many as 1 in 4 backup

tapes suer rom some sort

o problem that precludes

perorming a recovery.


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The Proven Solution

Double-Take Availability for AIX

, rom Vision Solutions, is designed to resolve the ollowingcommon problems:

Backup window: Data is continuously and transparently copied rom designated servers

throughout the day as changes occur, so you never again have to concern yoursel with

backup windows.

Recovery Point Objective: Using a technology called continuous data protection (CDP),

Double-Take Availability will allow you to retroactively pick any previous point and generate a

readable, writable snapshot o what the data looked like at the selected point; this eectively

presents you with all possible recovery points to minimize data loss on recovery in a way

that tape, with its limited number o recovery points, never can.

Recovery Time Objective: Double-Take Availability restores directly from disk, providing

you with fast, reliable restores in a way that tape cannot. And your ability to pick the optimal

recovery point to minimize data loss means that you will spend less time restoring the

entire application environment; this eectively shortens the downtime associated with data

recovery and hence the impact and cost o an outage.

Redundant Application Server:The backup server provides a manual ailover target that

will allow a critical application to be rapidly restarted with access to current data (to allow

processing to continue i the primary server or some reason cannot be restarted).

Remote replication: Double-Take Availability includes the ability to replicate data across IP

networks so you can migrate your aged data to a remote acility without exposing it to the

risks associated with the physical transport o tape-based media.

Double-Take Availability is already in use with referenceable customers across different vertical

markets, including nancial services and healthcare. It runs on IBM Power Systems servers with

AIX 5.3 and above and is applicable to any application running on AIX. Applications for which

Double-Take Availability is a good t meet the following prole:

A 7 x 24 application environment with a small to non-existent backup window.

Critical applications (from a business point of view) that have high rates of data change

(where ewer recovery points translates to signicant amounts o lost data on recovery).

Applications with stringent recovery time requirements that are not currently being met withexisting data protection technologies.

By 2011, some orm o CDPwill be deployed in 80 percent

o the Fortune 2000.

Gartner


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How Does the Double-Take Availability Solution Work?

A dedicated backup System p server is established, and can protect one or more applicationsrunning on other IBM AIX production servers that are connected to it locally via an IP-based

network. Double-Take Availability mirrors production server writes to designated Protected

Storage (the storage where the application you want to protect resides) to the backup server

over IP. These writes are stored in the Recovery Storage that is directly attached to the Backup

server. Double-Take Availability runs continuously in the background and does not noticeably

impact the performance of the Protected Application.

At any time, an administrator can go into the management interface of the Backup server,

running on a separate Windows-based PC, and generate a historical view (a snapshot of

the data at any randomly selected previous point in time). These historical views can then be

presented to any other server on the network or the purposes o recovery or to perorm any

type o o-host processing. These historical views are ully read/write capable, which means

that they can support o-host processing tasks like data analysis, testing, development

or backup all without imposing any impact whatsoever on the Protected Application. A

historical view can be presented back to the production server as well, but note that there is

another option with respect to the production server, called Production Restore, which uses

dierencing technology to modiy the Protected Storage to look like the historical view selected

on the backup server.

Most restore requests are

driven by issues such

as an inadvertently deleted

fle or data corruption

that is introduced by a

virus or a hacker.

Figure 1. Double-Take RecoverNow mirrors data to a local backup server, which can then retroactively

present snapshots or recovery, analysis, testing or development purposes with no impact

on the production server(s).

Data Tap

Protected Server

Ethernet (IP) network

LAN

IBM Server

Snapshot presentation

Manual failover target

provides server-level

redundancy

Protected Storage Recovery Storage

Production restore

AIX 5


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Double-Take Availability also supports asynchronous replication. This allows you to replicate

the continuous data stream or selected historical views to a remote acility, as long as it is

connected to the primary acility by an IP-based network. Replication o the continuous data

stream provides ull any point in time recovery capabilities at the remote site. This conguration

is optimal or disaster recovery capability, since historical views created at the remote site can

only be presented to servers at the remote site that are on the same LAN as the remote backup

server. Replication represents a much aster, much more secure way to get your data to an

osite storage acility. To use this eature, you will need to purchase another System p server

running AIX and the backup server software license at the remote site.

n optimized recovery window

seven days is confgured on

the Backup server...

Any restore requirement dur-

ing that seven day period is

perormed instantaneously

rom disk, without the need

o build up a restore image

rom multiple incremental

backups.

Protected Server

Snapshots created by the

IBM Server can be presented

to a Backup Server for any

type of off host processing,

like backup.

Snapshots created by the

IBM Server can be presented

to a Recovery Server to

recover a production application.

IBM Server

Backup Server Tapes can then be

transported off site

for remote storage.

IBM Server Recovery Server

IP-based replication

WAN

LOCAL SITE REMOTE SITE

Data Reference Patterns

100%

50%

0%

Online(ms)

Retrievalactivity

Amount of data

Nearline(sec)

Archival/deletion(sec/mins)

References declineas data ages.

Data is being kept forlonger periods of time.

The percent of total datadeleted is declining.

TCO encourages migrationof less active data.

Days since creation

1 3 7 15 30 60 90

Source: Harison Information Strategies


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The Correlation Between Data Age and Possibility of

Re-Use/Restore

It has been proven over time that most data recovery requests are or relatively recent data,

and that there is a direct correlation between the age o data and the possibility that it would

be required or restore purposes. Most restore requests are driven by issues such as an

inadvertently deleted le or data corruption that is introduced by a virus or a hacker. Typically

these problems are discovered within several hours or at most a ew days rom when they rst

occur, resulting in restore requests or more recent data.

In general, the only time you may need to restore data that has already been archived would

be in the event o a disaster that physically destroys computer equipment and acilities, such as

an earthquake or a tornado. While it pays to be prepared against these occurrences, they are

very rare. The slope o the red line in Figure 3 varies by company type, but it refects the general

relationship in all industries between the age o data and the chance that it would need to berestored.

Another key factor to note is that as data ages, it becomes less important to support the ability

to restore to any point in time. Note the inection point in the red line in Figure 3 that occurs

around Day 3. Restore requests or data drop o signicantly ater that point. This might suggest

that you would want to manage roughly 3 days worth o your most recent data with Double-

Take Availability, migrating it to less exible but less expensive media locally thereafter for several

weeks, and then eventually storing it in an o-site acility ater about 30 days. This 3 day window

is reerred to as the optimized recovery window.

Two Sample Use Cases

Using Double-Take Availability to Provide Zero Impact Data Protection and Rapid

Local Recovery

In this scenario, we assume the customer wants to solve the rapid recovery problem at the local

level. They have chosen, however, not to replicate and will continue to migrate data to tape or

physical shipment to an osite location.

The customer is running an Oracle database as an order entry system on an IBM Power

Systems server with AIX and 600GB of internal storage. This server will become the production

server.10% o the data changes on a monthly basis, and the overall rate o data growth is

orecast at 30% per year. Based on past experience, the customer knows that restore requests

tend to drop o signicantly ater seven days. The customer currently does daily incrementalbackups and weekly full backups using a 100 Mbit Ethernet LAN. Incremental backups take

roughly 90-120 minutes per day, while the ull backup takes between ten and teen hours using

a small tape cartridge autoloader.

To install the Double-Take Availability solution, the customer purchases a second IBM Power

Systems server on AIX to act as the backup server. Based on the rate of data change and

forecast database growth, 1.5 TB of Recovery Storage is housed internally to the backup

server. This backup server is attached to the same LAN as the production server. Double-Take


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Availability is installed on the production server, while the relevant storage which underlies the

Oracle application is designated as the Protected Storage. An optimized recovery window of

seven days is congured on the backup server. An initial synchronization between the production

server and the backup server is perormed while the production server continues to run (itis run as a background process) so that database access is not impacted. Once the initial

synchronization is complete, continuous data protection is enabled.

To take advantage of the capabilities of their newly implemented Double-Take Availability

solution, the customer makes some changes to their data protection processes. With seven

days o data included in the optimized recovery window, the customer no longer needs to

perform daily incrementals. Any restore requirement during that seven day period is performed

instantaneously rom disk and without the need to build up a restore image rom multiple

incremental backups, thus cutting recovery time to minutes.

A weekly tape backup is still desirable to prepare for the eventual archiving of data offsite, but

the Oracle application no longer needs to be shut down to perorm backups. Once a week, a

historical view is created by the backup server, which then uses it to perorm a tape backup. The

customer continues to use its existing tape backup sotware to perorm this backup. Double-

Take Availability is compatible with all backup software packages for the purposes of historical

view presentation or o-host backup. These tapes are kept onsite or two weeks, and then sent

to an osite acility or archival storage.

Implemented in this way, Double-Take Availability for AIX provides the following benets:

Backups to tape are now completely decoupled from the production application so they can

now be scheduled to occur when it is convenient or the administrator, without concern or

impact on business processes.

Backups are only taken once a week now (instead of daily), taking less administrative time.

Restores within the optimized recovery window occur rapidly and reliably from disk,

completely resolving tape media integrity issues or near term restores.

Data loss on recovery is minimized because the administrator now has access to the

optimal recovery point to minimize data loss or every conceivable ailure scenario (this is the

RPO issue).

Recovery time is shortened in several ways:

no restore from tape to disk is required (the application can just be started right up on

the selected historical view).

a recovery point never needs to be built up from incrementals so there is less

administrative overhead associated with recovery (the selected point is just immediately

presented rom disk).

there is less time spent preparing the application for production use again after the

recovery because the best recovery point to resolve the problem can be selected (e.g.

i the problem is a le deletion or data corruption problem, the point right beore that

event occurred can be chosen).


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Recovery time is considerably shortened in the event of a problem with the production

server: The Protected Application is simply started on the backup server, using the latest,

current copy o the production data (the latest historical view). It can continue to run there

until such time as the production server can be repaired and restarted.

In addition to these benets, there is another advantage that did not exist with the previous

tape-based approach. Patched and upgraded applications can be tested against current

production data in a manner completely decoupled from the production environment. A

historical view o the current data state is created and presented to a staging server (also on

the LAN) where the patched or upgraded application can be tested. Once the administrator is

satised with the stability o the new environment, it can be deployed in production. Double-Take

Availability makes it easy to create these historical views for testing purposes, ensuring more

reliable patch and upgrade processes against production environments.

Archiving To Tape with A Multi-Site Double-Take Availability Confguration

In this scenario, we assume the customer wants to solve three problems (backup window, RPO

and RTO) but they also want to migrate their archival data to a remote acility with minimal risk.

For the purposes o this example, well assume they are running an IBM DB2 UDB database on

an IBM Power Systems server with AIX.

Adding to their production server, the customer purchases a local backup server with an

appropriate amount of storage, and the Double-Take Availability software licenses. Then, to

enable the remote replication capability, the customer purchases another IBM Power Systems

server, to be located at the remote site, running the same operating system.

The customer wants to take the weekly ull tape backup rom disk at the remote site or

archival storage. Both the local and remote backup servers are connected via an IP network.

With this conguration, the only change to their ormer backup processes is that they now keep

no tape at all at the local (production) site, only at the remote site.

Once a week, a historical view that represents the ull backup is created on the remote-site

backup server. The remote backup server then backs up the data to tape. Recoveries o data

that is already archived can be restored rom tape to disk on the remote backup server, and

then replicated back to the local (production site) backup server. At that point, the view can be

manipulated or any recovery or o-host processing purposes in the same manner as any locally

created view.

This solution provides the ollowing benets:

All of the benets of the local conguration example accrue here, including removal of thebackup window, minimized data loss and much more rapid, reliable recoveries (due to rapid

restores direct rom disk and to the availability o the backup server as a manual ailover

platorm).

The additional advantages that accrue with the remote conguration include a fast, easy and

secure way to migrate data rom a local site to a remote site without incurring any o the risk

associated with physical transport, and a ast, easy and secure way to get that data back to

a local site on those rare occasions when a recovery rom older data is required.

Tape-only backups are no

longer a easible data

rotection strategy in todays

business environment


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15300 Barranca Parkway

Irvine, CA 92618800-957-4511

801-799-0300

visionsolutions.com

Copyright 2010, Vision Solutions, Inc. All rights reserved. IBM and Power Systems are

trademarks of International Business Machines Corporation. W indows is a registered trademark

of Microsoft Corporation. Linux is a registered trademark of Linus Torvalds.

Recovery Time Comparisons

When downtime costs you money, a rapid

recovery capability presents a quantiable returnon investment opportunity. By oering a much

aster and easier way to perorm data recovery

than that oered by tape, savings accrue not

only in the area o downtime but in terms o

administrative time and expense. As shown in

Figure 4 below, Double-Take Availability can

shorten recovery times by hours and even days

in some cases.

Summary

Any business that is experiencing rapid growth

or consolidation is very likely using a suboptimal

data recovery solution built around tape-based

backup. This type o legacy solution potentially

interrupts business processes, due to the

requirement or a backup window, subjects the business to potentially signicant data loss

when recoveries are required, and is time consuming and labor intensive or both data protection

operations and recoveries.

Double-Take Availability for AIX is a proven solution to the data recovery problem that is in use

at a variety of referenceable accounts today. Double-Take Availability leverages CDP technology

to support instantaneous recoveries rom disk, resulting in minimal data loss (due to its abilityto present all possible recovery points), rapid, reliable recovery (due to its ability to restore

immediately rom disk), all while not imposing any downtime on production applications (zero

impact data protection).

Because Double-Take Availability ensures that data on the backup server is always current,

it can be relied upon as a manual ailover platorm that allows application processing to be

rapidly restarted in the event o a catastrophic production server ailure. In addition, Double-Take

Availability supports asynchronous replication that will allow businesses to establish cost-

eective and secure multi-site disaster recovery strategies that support rapid recovery, even

from archived data. Double-Take Availability runs on IBM Power Systems servers with AIX and

is applicable to any AIX application, but is applied most often for use with business- or mission-

critical applications such as enterprise databases or le systems.

Recovery Time for 1 TB of Data

Review & Roll back from Historical View

Apply Roll Back to Production Se rver

Double-Take RecoverNow Recovery

RebuildVolumes

Apply Archive Logs

ResynchronizeVolumes

Apply Archive Logs

Restore Data Files from Tape

Apply Archive Logs

IBM

Hours

Local Offsite Tape

20

15

10

5

0

Recovery from Local Copy

Recovery from Offsite Copy

Recovery from Tape

3 Hrs

20 Min

9 Hrs

17 Hrs

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