In today’s information age, protecting critical data of an organizati on’ s branch offices, across multiple locations, should be standard practice. However, delivering a robust data protection strategy in environments with limited resources and often untrained personnel, can prove challenging. IDC quantified the size of this challenge: one-fifth of large companies have over 50% of their data in remote offices 1 , and another one-third of large companies have 20-50% of data in their remote offices. Very often, business-critical data at remote or branch office (ROBO) locations is inadequately protected, exposing the business to greater risk of lost data and lost productivity . F E E N DD Data Protection for businesses with remote offices across multiple locations Business white paper 1 IDC Special Study – Hyper consolidation in the Remote Branch Driving Spend - October 2009
Introduction A study conducted by industry analyst EnterpriseStrategy Group found that the top three IT prioritiesfor remote office / branch office (ROBO) locationswere driven by business priorities: to improveinformation security, ensure regulatory compliance,and enhance disaster recovery2. However, themany choices in data protection technologies andapproaches, coupled with a wide range of vendors
to choose from, can make data protection planninga daunting endeavor.
This white paper drills deeper into these challengesand the considerations for a better way to approachdata protection. It also explains how the HP dataprotection portfolio can help businesses overcometheir data protection challenges, and drive betterbusiness outcomes. The white paper includes aglossary, defining terms used to expand dataprotection approaches, and where customers canfind further information on HP data protectionofferings.
Figure 1. Enterprise deploymentwith small and large ROBOs
2 Enterprise Strategy Group Research Report: Branch Office Optimization, 2007
Day-to-day realities for ROBOdata protectionRemote office/branch office data backup and restorehas always been a challenge for IT managers. Someof the challenges include:
•Facingthechoiceofusinguntrainedpersonneltomanage the increasingly complex physical tapeinfrastructure, or hiring resources to manage databackup tasks at remote sites
•Payingserviceproviderstocollect,store,andretrieve tapes between remote and central offices
•Meetingabackupwindowwithoutextendinginto normal business hours, and affecting criticalbusiness applications
•BackingupdataoverthecompanyWANtoacentral site being restricted because of the timeand cost involved in sending relatively highvolumes of data to be backed up over a relativelylow-speed link
•Unabletoprovetoauditorsthatacomprehensivesite disaster recovery plan exists
What is your vision of an idealdata protection solution?
A business with multiple locations should notstruggle with inefficient or ineffective data protectionprocesses. Hardware and software solutions for databackup and restore should be easy to integrate into
the existing environment, provide easy-to-managedata protection regardless of the IT expertise, andclearly demonstrate cost efficiencies. This visionmust also realize that the ROBO and the associateddata centers are very different in terms of costsrequirements and performance expectations, andrequire different technologies. Ideally, a dataprotection infrastructure should result in:
•Spendinglesstimeonphysicaltapemanagement,and a reduction in the risk of human media-relatederrors
• Automatingprocesseswithasinglemanagementconsole across the entire backup environment
•Effectivestoragecapacityutilization,retainingbackup data close to hand for as long as possiblefor rapid single file restore
•Usingbackupandrestoretechnologiesforfastbackup of file servers and a reduced backupwindow
•Easymaintenanceandmanagementofbackupcopies in multiple locations
•MakingthebestuseofexistingWANlinksfromROBO sites to regional data centers
•Thecapabilityofmultiplelayersofdataprotectionto meet with ranging service level agreements, and
levels of risk.
With HP ROBO solutions, data is accessiblewherever it is required; in some cases, this may bein three different locations and on physical tape forgreater flexibility in restore or disaster recovery (DR)options. With ability to manage data backup ordata restore through a single backup application,IT personnel with relevant expertise can recover thedata from the ROBO appliance at multiple ROBOlocations, and manage the data recovery processfrom the main/regional data center.
HP StorageWorks D2D (Disk-to-Disk) BackupSystems, HP StoreOnce deduplication technologyand HP Data Protector software can provide acomplete solution for distributed office environments. Additionally, HP StorageWorks VLS (VirtualLibrary Systems) provide higher capacity, higherperformance deduplication solutions for enterprisedata centers.
Solution scenario summaryForanoverviewoftypicalprofiles,dataprotectionissues, and HP data protection capabilities, thistable provides a quick comparison across threetypical scenarios. Detailed scenarios are visuallyrepresented in the next section.
Table 1. Solution scenariosummary
Scenario one Scenario two Scenario three
Typical sizing 200+ ROBO’s with full
backup size of 100 GB andincremental backups of 10%
100+ ROBO’s with 200-500GB full backups
100+ ROBO’s with 200-1 TBfull backups
PLUS
Upto4regionaldatacenterswith 7.5TB to 300TB backupsrequiring DR solution
Problem Large number of ROBO siteswith small backup volumes
Significant backup volumeat remote sites and arequirement for local recoveryat the ROBO site
All above data requiring tobe consolidated at main datacentre
Solution HP Data Protector Syntheticfull backups over WAN to HPD2D with NAS Emulation
•Upto50:1fan-infromsmallHP D2D units in the ROBOto larger consolidated singleHP D2D4312 in the datacentre
•HPReplicationManagersoftware to managemulti-site replications.
•Offloadtophysicaltape if required
•HPD2DforROBO’s,replicating to a larger D2Dat the Regional Data Center
•HPD2DorVLScopiesoflocal data at the regionaldata centre using HP dataprotector copy functionality
• AdditionalreplicationtoD2D or VLS in the main datacenter for disaster recovery
Why HP Synthetic full functionalit y
allows object consolidationand ensures only smallvolumes of data transmittedover WAN
Scalable up to 100s of ROBOsites
Recovery to ROBO from datacentre under data centrecontrol
Only HP offers a low cost
entry point to deduplicationreplication for ROBO’s(sub $5000)
UniqueHPStoreOncededuplication technology
Target D2D can beperiodically tape to tapecopied to physical tape usingspecial functions in HP DataProtector
End to End control from HPdata protector
Only HP offers both a low cost
entry point to deduplicationand replication (using D2D) AND a choice of highlyscalable, appliances (D2Dor VLS) for data centerenvironments
Target VLS can be periodicallytape to tape copied tophysical tape using specialfunctions in HP data protector
•Objectconsolidationusingsyntheticfullbackupstoreduce WAN traffic
• VariableRetentionpolicies.ShorttermonD2D,long term on tape for archive
•FastrecoveryfromD2D4106withNASemulation
•HPDataProtectormanagestheentireprocessfrom the main data centre
•ReducedWANutilization.Notinthiscase,itissynthetic full that reduces traffic not D2D
However, there are some constraints associated withthis solution, including:
•Itdoesnotprovidealocalsourceofthedataforrecovery. A synthetic full created at the regionalcentre is required and the necessary files to berestored need to be transferred over the WAN.
•Thetimeforthisrecoveryprocesstocompletedepends on the size of the WAN connection andthe amount of data being transmitted.
Solution scenarios
The scenarios discussed below cover a wide rangeof implementations that are possible using HP D2DBackup Systems and HP Data Protector Software,from a small business that has several outlets toa major corporation that has hundreds ofremote/branch offices, several regional data
centers and multiple main data centers.
Forinformationontheenablingtechnologiesforthese solutions, please refer to the appendices.
Scenario one:
Cost-effective remote office backup with low
WAN traffic
Solution:
Client-based backup over the WAN using HP
Data Protector synthetic full functionality
In this first scenario, we follow a basic client agentbackup process, suitable for a large number ofROBO sites where relatively small amounts of data
need to be protected. In order to reduce the amountof data that needs to be transmitted over the WAN,customers can use the “synthetic full” feature ofHP Data Protector. After the initial full backup onlyincremental backups need to be performed. Thebackupdataissenttoa“FileLibrary”device(inthis case a NAS share with deduplication on theD2D4106 unit), where a “synthetic full” can becreated at any time for a restore. Alternatively, thereis another feature in HP Data Protector called “virtualfull” that is similar to synthetic full, but uses lessstorage space. However, it can only be implemented
on a file library device, such as an HP P2000 diskarray.Finally,underHPDataProtectorcontrol,thesynthetic fulls can be copied to physical tape forlong-term archiving.
Note: the HP StorageWorks D2D4106 Backup System offers up to 9TB of usablecapacity. This can be extended to up to 180TB over time with HP StoreOncededuplication at a factor of 20x.
Figure 2. Client based backupover the WAN using HPDataProtectorSyntheticFullfunctionality
The HP D2D replication license also entitles the usertoHPReplicationManagersoftwaretoprovidecentral management capabilities for multi-sitereplication.
TheHPDataProtectorCellManagercanbescripted to poll the D2D4312 on a regular basis todetect replicated cartridges and update its internaldatabase (IDB) with their contents. As a result, inthe event of a disaster at the ROBO, the regionalcenter is immediately aware of which virtual tapesarerequiredforrecovery.Finally,datafromthe
D2D4312 at the regional center can be easilycopied to physical tape at regular intervals using the“object copy” functionality within HP Data Protector.In addition to acting as a replication target forROBO sites, the D2D4312 can also act as a sourcefor backups from the regional center servers as seeninFigure3.TheD2D4312offersbothdual8GbFCand dual 10 GbE connections for the local backupsin the Regional center.
This solution provides robust disaster recovery. Ifa disaster occurs at the source (ROBO), the data
remains safe at the target (regional data center). TheROBO site can then be re-constructed in any of thefollowing ways:
a. Re-building a new ROBO server and restoringdata at the regional center using the replicated data
b. Re-building the server at the ROBO site andreverse replicating the critical data from theD2D4312 in the regional center
c. Offloading critical data to tape at the regional
center and transporting it back to the ROBO with thenecessary tape hardware for recovery
Scenario two:Backup consolidation and cost-effective disaster
recovery for larger ROBOs
Solution:
HP StoreOnce enabled replication using HP
StorageWorks D2D2502/4i in ROBO and HP
StorageWorks D2D4312 in Regional Center all
managed by HP Data Protector - for up to 50
remote sites.
In this scenario, the volumes of data on theremote sites are much larger, around 500 GB,and customers really need to have local restorecapability. Each remote site has a local D2D2500series appliance (D2D2502 or D2D2504i) withHP StoreOnce deduplication and the D2D uses thevirtual tape library emulation mode. A user capacityof 1.5 and 3TB can yield between 30 and 60TB ofbackup storage with a 20:1 deduplication ratio afterseveral backups have been retained over two – threemonths. If long retention is not required then theD2D2500 can support even larger backups retainedfor shorter periods.
Direct restore at the ROBO from the D2D unit ispossible since each ROBO site contains a completeData Protector environment of cell manager andmedia server and is “self-sufficient” from a restoreperspective. The local D2D2500s (sources) can alsobe configured to replicate only the changed dataacross a low-bandwidth link to the regional centerwhere a larger D2D4312 (target) device resides. A D2D4312 can support a fan-in of up to 50 D2Dsources and only requires a single HP ReplicationManagersoftwarelicensefortargetdevicesto
enable replication. Source devices use ReplicationManageratnocharge.Thisallowsmajorstorageconsolidation benefits at the regional data center.The replication process replicates the changes invirtual cartridges from the ROBO to the regionalcenter.
Figure 3. Large scale ROBOdeployment - end-to endreplication with regional datacenter consolidation
The new area of interest here is the low-bandwidthlink.ForthemajorityofROBOsiteslinkspeedsaslowas2MB/seccanbeused(dependentonvolumes of data to be replicated). Different usagemodels may be used to enhance the businessbenefits of network efficient replication, including:
•Use100%ofthelinkbandwidthtocompletereplication in a fixed window (12 hours). This is forbusinesses that are not necessarily 24x7 and can
afford a window dedicated to replication.
• WithintheD2Dunititispossibletoconfigure“throttling” of the link and allow the replicationto take place over a 24 hour period. This isfor businesses that also use the WAN link forapplications, and where giving the whole linkover to replication would affect other applicationperformance.
To calculate the size of the regional center D2Ddevice and the size of the link required (either with
fixed window or with throttling) HP provides acomprehensive sizing tool available at:http://www.hp.com/go/storageworks/sizer
Benefits
•Locallyperformedandcontrolledbackups,reliability of backups not dictated by WANavailability, and remote media server as inscenario one
•Fastlocalrecoverywhenneededfromtwobackupcopies (one local and one remote)
• Abilitytostoreseveralmonthsofbackupslocallyon the D2D at the ROBO using HP StoreOncededuplication
•Significantbandwidthreduction—upto95%savings in bandwidth compared to all contentsbeingreplicated—ratherthanjustchangedatadetected by deduplication
•Cost-effectiveconsolidationintheregionalcenter
up to 50 ROBO D2Ds (fan-in). In addition, theD2D4312 can also be used to consolidate localregional server backup
•Highlyflexibledisasterrecoveryoptions
•EasyoffloadtotapewithHPDataProtector object copy
•Managementoftheentireprocessfromthemaindata center by HP Data Protector
•OptiontomanagesingleROBOsfromtheregional/main data center
As for scalability – the example above shows a 50:1fan-in, if a customer environment has more than50 ROBO sites, the customer would need multipleD2D4312 devices at the regional data centre.8
This solution with VLS allows consolidation at themain data center. The VLS9000 there is used both asa replication target for the four regional data centersand for main data center backups as well, providingan excellent solution for consolidation.
Replicated cartridges from the regional centerarriving at the VLS target in the main data centersend an e-mail on an hourly basis to the DataProtectorCellManageratthemaindatacenter.
The Data Protector scripts then import these newlyreplicated tapes into the backup catalog at the maindata center to allow easy access to replicated datawhen disaster recovery becomes necessary for theregional data center.
A further enhancement to this scenario would be tohave active-active replication, where the main datacenter backups to the VLS are also replicated backto the regional data center, giving the main datacenter a very cost effective disaster recovery processusing the existing infrastructure. Due to the different
nature of D2D and VLS deduplication technologies, itis not possible for D2D units to replicate directly intoa VLS unit.
The disaster recovery options for the regional datacenter using VLS are identical to those used for D2D. Again, with the higher volumes of data involvedbetween regional data centers and main datacenters, HP expects the usage model for VLS to VLSreplication to be predominantly:
VLS replication sizing is also fully supported in theHP StorageWorks Sizing Tool at:http://www.hp.com/go/storageworks/sizer
Scenario three:
Scalability, consolidation and data center
resilience
Solution:
Network-efficient replication over
low-bandwidth links using HP StorageWorks
D2D for replication between ROBO sites and
regional centers, and HP StorageWorks VLS
Backup Systems with HP Data Protector software
for replication between regional centers andthe main data center. HP Replication Manager
software facilitates multi-site replication through
central management capabilities.
In this scenario, the volumes of data involved atthe regional data centers are significantly highand the need for scalability paramount.HP enterprise-level Virtual Tape Libraries (VLS) areused because they can scale higher in terms ofcapacity and performance than the HP D2D BackupSystems. An alternative configuration could bemultiple HP D2D4312 Backup Systems.
The ROBO to regional center solution is the same asin scenario two. However, instead of local regionaldata center backups being done to the HP D2D,the regional data center volumes (greater than 30TB) are now backed up to a local VLS9000 device.In this case the VLS9000 can scale to capacitiesbetween 10TB and 1280TB of data.
VLS systems also support network efficientreplication of data over lower bandwidth links, andcurrently support up to a 4-to-1 fan-in that enablesconsolidation of replications from several regionaldata centers in a single VLS9000 target device atthe main data center. The VLS9000 uses amulti-node architecture to provide scalability interms of backup performance, as well asdeduplication and replication performance. Giventhe higher volumes of replicated data involved, thelower bandwidth links for VLS are typically 100Mbits/secupwards.
Figure 4. ROBO and regionaldata to primary data centers –
HP Data Protection portfolioThe three scenarios described above give you aninsight into the various ROBO and regional datacenter disaster recovery deployments that are
possible using the following HP storage components:HP D2D Backup Systems with HPStoreOnce deduplication Provide disk-based backup, retaining up to 50xmore data on disk, with low bandwidth replicationfor cost-effective data protection of distributed officeenvironments with multiple servers.
HP Virtual Library Systems Offer high-performance, scalable data protectionsolutions in demanding data center environmentswith accelerated deduplication and enabled
replication.
HP Tape Systems (standalone tape drivesand tape automation products) Choice of physical tape libraries designed to provideunattended backup, archive, and disaster recoveryfor businesses of any size.
HP Data Protector software With limited resources and tight budgets, HP DataProtector software automates high-performancebackup and recovery from disk or tape to enable24/7 business continuity at a compelling
price-to-performance ratio.
Usingthewiderangeofcomponentsallowsflexibility and scalability in the variety of ROBOand data center backup solutions that can beconstructed. With innovative technologies such asthe synthetic full functionality, deduplication, andlow-bandwidth replication on VTL products, HPcan deliver a highly effective solution that helpsprovide peak performance at the best possible costfor each specific location, while enabling centralmanagement and control.
Appendix A – HP StoreOncededuplication is the key enabler forcost-effective data replicationData deduplication is a method of reducing storage
needs by eliminating redundant data, so thatover time only one unique instance of the data isactually retained on disk. Data deduplication worksby examining the data stream as it arrives at thestorage appliance, checking for blocks of data thatare identical and eliminating redundant copies. Ifduplicate data is found, a pointer is establishedto the original set of data as opposed to actuallystoringtheduplicateblocks—removingor “de-duplicating” the redundant blocks from thevolume. However, indexing of all data is stillretained so that it can be “rehydrated” shouldthat data ever be required.
The key here is that the data deduplication isbeing done at the block level to remove far moreredundant data than deduplication done at the filelevel (called single-instancing), where only duplicatefiles are removed.
By its very nature, the backup process tends togenerate a great deal of repetitive copies of data,and hence data deduplication is especially powerfulwhen it is applied to backup data sets. The amountof redundancy will depend on the type of databeing backed up, the backup methodology and thelength of time the data is retained.
Once the original file is stored the technologyeliminates duplicate data down to the block or bytelevel on all future changes to that file: If a change
is made to the original file, then data deduplicationsaves only the block or blocks of data actuallyaltered,(a block is usually quite small, less than10KBofdata.)Solet’ssaythetitleofour1MBpresentation is changed. Data deduplication wouldsave only the new title, usually in a 4 KB data block,with pointers back to the first iteration of the file.Thus, only 4 KB of new back up data is retained.
When used in conjunction with other methodsof data reduction, such as conventional datacompression, data deduplication can cut datavolume even further.
HP StoreOnce deduplication software deliversimproved performance at half the price point ofcompetitive solutions and enables clients to spend upto 95 percent less3 on storage capacity comparedto traditional backup. HP StoreOnce software isavailable in all HP StorageWorks D2D backupsystems, providing a single technology that canbe deployed at multiple points in a convergedinfrastructure.
Appendix A - continuedReplication of data can occur between deviceswithin the same product family i.e. between theHP StorageWorks D2D2500, D2D4000, D2D4112
and D2D4312 Backup Systems. It is not possible toreplicate data from D2D to the VLS product rangesnor to competitors’ disk based backup systems withreplication features. HP D2D & VLS devices use adifferent implementation for deduplication, eachdesigned to be most appropriate to the target marketin terms of ease of use and affordability.
Data replication is the process of making a replicacopy of a data set across a network to a “targetsite”. It is generally used to transmit backup data setsoff-site to provide disaster recovery (DR) protection
in the event of catastrophic data loss at the “sourcesite” In the past, only the largest companies couldafford to implement data replication as replicatinglarge volumes of data backup over a typical WAN isexpensive.
However, because StoreOnce deduplication knowswhat data has changed at a block or byte level,replication becomes more intelligent and transfersonly the changed data as opposed to the completedata set. This saves time and replication bandwidth
making it possible to replicate data over lowerbandwidth links for a more cost-effective, networkefficient replication solution.
HP D2D Backup Systems with StoreOnce provide anautomated and practical disaster recovery solutionfor a wide range of data centers, in addition to anideal solution for centralizing the backup of multipleremote offices.
Figure 6. Deduplication is keyto enabling more affordable,network efficient datareplication between sites.
UsingHPD2Dmeetsrestoreperformance service levels,adding periodic offload totape adds a level of protectionand meets long-term archivalrequirements.
3 Based on multi-site deployment of D2D4312 ROI calculations as replacement technology for pure tape backup and offsitearchival(HPD2DTCOAnalysisfromMay2010)4 Based on average deduplication ratio of 20:1. Deduplication ratio could be as high as 50:1 under optimal circumstances.
Appendix B – HP Data ProtectorSyntheticFullBackupHP Data Protector software offers an advancedbackup solution called synthetic full backup. This
solution enables you to create synthetic full backupsand virtual full backups with an operation calledobject consolidation allowing implementing anincremental forever backup strategy.
Figure 7. HP Data ProtectorSyntheticFull(IncrementalForever)Backupexplained
Synthetic backup eliminates the need to run lengthyfull backups. This technology works by merging allincrementalbackupsintoafull‘synthetic’backup—aprocess that can be repeated indefinitely, with noneed to run a full backup again. If all the backups,
full and incremental, are written to the same HP DataProtector file library which uses a distributed filemediaformat(DFMF)e.gonanP2000diskarray,an even more efficient type of synthetic backupispossible.ThisiscalledVirtualFullBackup.Thesolution uses pointers to consolidate data rather thancopying the data. As a result, the consolidation takesless time and avoids unnecessary duplication ofdata. Only the HP Data Protector Synthetic backuptechnique is supported on the D2DNAS emulation.
This capability also helps enable continuous dataprotectionforWindowssystems.Forsystemsrunning Windows 2000 and above, HP Data Protectorutilizesthebuilt-inMicrosoftWindowsChange Journal to quickly generate a list of files that have
been altered since the last backup was performed.This option avoids the need for timely “tree walks”to identify files that have changed, which can beespecially time-consuming on systems with manysmall files. This allows incremental backups to runmuch faster and more frequently, providingnear-continuous data protection at noadditional cost.
Appendix B - continuedThe ‘incremental forever’ paradigm means thatexcept for the first backup where a full backup isperformed, only incremental backups are executed.This concept presents the most efficient way ofbackups; only the changed data is backed up.
However, without object consolidation, the restoreprocess would last far too long since all backupsessions would have to be restored. Due to this
behavior, regular full backups are required and allbackups would need to be protected permanently.Object consolidation removes this drawback.
During the object consolidation session, HP DataProtector software reads the backed up data fromthe source media, merges the data, and writesthe consolidated version to the target media. Thisconsolidation process taking place on the D2DNASdevice does take a significant amount of time.
An object consolidation can result either in asynthetic full or a virtual full backup.
A synthetic full backup is the result of an objectconsolidation operation where a restore chain ofbackup objects is merged into a new, syntheticfull version of this object. A synthetic full backup isequivalent to a conventional full backup in termsof restore speed. HP D2D NAS emulation supportssynthetic full backups.
A virtual full backup is an efficient type of syntheticbackup where data is consolidated using pointersinstead of being copied. It is performed if all thebackups (the full backup, incremental backups, and
the resulting virtual full backup) are written to asingle HP Data Protector software file library usingdistributedfilemediaformat.ThisrequirestheFileLibrarytobeadiskarraysuchasHPMSA2000.
Other HP Data Protectortechnologies explained:DHP Data Protector Cell Manager
•ContainstheIDB(InternalDataBase)-theIDBcontains information about backup details such as,
backup durations, media IDs, and session IDs
•RunscoreHPDataProtectorsoftware
•RunsSessionManagersthatstartandstopbackupand restore sessions and write session informationto the IDB.
HP Data Protector Disk Agents
Client systems you want to back up must have theHP Data Protector Disk Agent (DA), also calledBackup Agent, installed. To back up online databaseintegrations, install the Application Agent. The
Disk Agent reads or writes data from a disk on thesystemandsendsorreceivesdatafromaMedia Agent. The Disk Agent is also installed on the CellManager,thusallowingyoutobackupdataontheCellManager,theHPDataProtectorconfiguration,and the IDB.
HP Data Protector Media Server
Client systems with connected backup devicesmusthaveaHPDataProtectorMediaAgent(MA)installed. Such client systems are also called DriveServers. A backup device can be connected to anysystemandnotonlytotheCellManager.AMedia Agent reads or writes data from or to media in thedevice and sends or receives data from the Disk Agent.
HP Data Protector Object Copy
The Data Protector object copy functionality enablesyou to copy selected object versions to a specificmedia set. You can select object versions from oneor several backup sessions or object consolidationsessions. During the object copy session, DataProtector reads the backed up data from the sourcemedia, transfers the data, and writes it to the targetmedia.
This freely available toolhttp://www.hp.com/go/storageworks/sizer allows users to specify backup capacities, retentionschemes, data change rates, replication window,link speed etc and calculates likely backup storagecapacity required.
Active-Active
Replication from a Source device on Site A to aTarget Device on Site B and also replication from aSourced device at Site B to a Target Device at Site A.Other replication configurations include:
Active->Passive - replication from a Source toDestinationinonedirectiononly,andMany-to-Onewhich is replication from multiple sources to a singletarget device.
Deduplication ratio
The reduction in storage required for a backup (afterseveral other backups have taken place). The ratio ishighly dependent on:
•Rateofchangeofdata(forexample,10%ofthedata in 10% of the files)
This is the number of source appliances or librariesthat can channeled into a target appliance or library.
Link Speed
ThisisspeedinMbits/secthattheTelcoprovides
point to point or Any to Any to allow replication totakeplace.Thespeedscanvaryfrom2Mb/secto 1 Gb/sec. Increasing Speed means increasing cost.
D2D Replication Licence
Only one replication licence is required per targetdevice, this is a chargeable licence.
D2D Replication manager
This is a comprehensive utility which monitorscomplex D2D replication environments and isavailable free of charge when you redeem your
D2D replication licence.
Bandwidth Utilization (Throttling)
This is the amount of available bandwidth adevicecanbeconfiguredtouse.Forexamplethe D2D & VLS devices have network throttling
so they can be configured to use for exampleonly 20% of the available bandwidth.This prevents any single device from“hogging” the total bandwidth available,and allows replication to take place overlonger periods of time without affectingapplication responses using the same link.
Tape Offload
The preferred method of copying datafrom D2D to Physical tape is to use theISV (independent software vendor)
backup software so that multiplestreams can be offloaded to physicaltape at once improving copyspeeds. This approach also allowsthe backup software to track allcopies of the same data throughits internal database. Thistechnique can be applied for:
