Post on 01-Apr-2018
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APPLICATIONNOTE
FAQ: Vicom Data Migration Services
Asaproviderofturnkeydatamigrationservices,Vicomisoftenaskedhowourapproachcompareswithalternativemethods1beingconsideredbycustomers.
Amongthecomparisonsrequested,hostorserverbasedmigrationperformedbyin‐houseITstaffsarethemostcommonbecausethemethodisfamiliaranditoffersperceivedcostadvantages.However,asthesizeandcomplexityofSANshavegrownand24x7operationshavebecomemoreprevalent,companiesareturningincreasinglytooutsourcingandspecializedtoolstohelpminimizethedisruptiveimpactmigrationscanhaveonbusinessoperations.
Intheirsearchfornewsolutions,customersaskforinformationaboutmigrationmethods,speeds,projectduration,requiredserverandsystemoutage,anddataintegrity.Theirquestionsinclude:
• HowdoesVicom’stotal,turnkeyapproachcomparewithinhouse,hostbasedmigrations?
• WhataretheprimaryadvantagesofVicom’smigrationapproach?
• Whoareyourcustomers?
• HowdoVicom’sMaxSpeedandContinuousmigrationmethodscomparein:
- Migrationspeed?- Systemavailability?- Timetocompletion?
• HowdoesVicomverifythedataintegrityofitsmigrations?
Q: How does Vicom’s approach compare with in-house, host-based migrations?
VicomTurnkeyApproachtoDataMigrations
VicomSystem’sDMS(DataMigrationService)isaturnkeyserviceinwhichanexperiencedmigrationspecialistmanagestheentiredatamigrationproject,start‐to‐finish—frominitialplanningtoservercutover.Moreover,everyDMSmigrationisbackedbyamoney‐backguaranteeofon‐timecompletion.Thisguaranteeismadepossibleby:
• Apurpose‐built,migrationappliancethatmovesdataindependentofserversandstoragesystems,atspeedsofupto1terabyteperhour.
1Foranextensivesurveyandcomparisonofothermigrationmethods,seetheVicomSystemswhitepaper,“NewWatchwordsforNetworkedStorageMigrations,”November2007.
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Theapplianceiscapableofmigratingdatawhileserversareofflineoronline.
• SANvirtualizationtechnologythatsimplifiessystemandstorageconnectionbyeliminatingincompatibilitiesandtheneedfordriverandOSupdateinstallationsonhostsystems,includinglegacysystems.
• Automateddiscoveryandmigrationmanagementwhichreducesthelaborandhumanerrorassociatedwithcomplexmigrations.
• Aprovenmigrationprocessforplanning,discovery,migrationmanagement,andverificationthathasbeendevelopedinthecourseofdeliveringofover500enterprisedatamigrations.
• Anon‐intrusiveandsecuremigrationmethod,performedwithouttheneedforsoftwareagentsorsystemmodifications,“musts”formanysecurity‐sensitivefinancialandgovernmentapplications.
• Experiencedmigrationspecialistswhooverseetheprojectfromstarttofinish.
Vicom’sprincipalobjectiveistodeliveryaproblem‐free,on‐timemigrationatanaffordableprice.WhileVicomreliesmainlyonitsSANbasedhardwareDataMigrationAppliancetomigratedatainfast,offlinemodeorcontinuous‐accessonlinemode,wealsousehost‐basedsoftwaretoolsasneededtoperformsupplementalservices,suchasLUNconsolidationandNASmigrations.Thissolution‐orientedapproachenablesVicomtohandledatamigrationsmoreeffectivelythananyotherserviceprovidersinthestorageindustry.
Figure1.VicomAppliance‐BasedOfflineandOnlineMigration
InHouse,HostBasedMigrations
Host‐basedmigrationisafrequentchoiceofITmanagers,especiallyforsmallerdatamigrations.Becauseexistingdataiscopiedorreplicatedbetweentheoldstorageplatformandanewerone,anyofseveralmethodsofdatareplicationemployingserver‐processingpowermaybeused.Typically,dataismigratedbetweenoldandnewstoragesystemsbymirroringdatavolumeswithastoragemanagementapplicationorcopyingfilesusingnativeOStools.Insomeinstances,third‐partydatamigrationapplicationsarealsoused.
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OneoftheprincipalreasonsITmanagersselectin‐house,host‐migrationmethodsislowerout‐of‐pocketcosts,particularlywhennativeOSutilitiesareused,sinceadditionalhardwareandsoftwarepurchasesarenotrequired.Relianceonexistingutilitiesandsystemsoftwarealsoeliminatestheneedfornewapplicationqualificationandtraining.Whenused,mirroringorfile‐copymethodsalsoenablecontinuousserveraccesstothesource(old)storagewhiledataismigratedtothenew(target)storageinthebackground.Fromaprojectmanagementstandpoint,datasetsmaybemovedindividuallyandreorganizedatthesametime—agoodoptionwhenthemigrationisrelativelysimpleandsmallinscale.
Bycomparison,specializeddatamigrationsoftwareapplicationsareoftenpreferabletonativesystemutilitiesbecausededicatedtoolscanprovidebetter,moretailoredcontroloverthemigrationprocess.Whenmigrationsoftwareisconsidered,automationanddiscoveryshouldbeamongtheprincipalreasonsforitsselection.Ataminimum,thesoftwareshouldincludemechanismsforSANdiscovery,migrationplanning,andactivemigrationmanagementandcontrols.Itshouldalsobenotedthathost‐basedmigrationsoftwaretoolsaretypicallylimitedintheirrangeofplatformcompatibilitybecausetheymustbeportedtovariousoperatingsystems.WhilethesetoolsmayworkwithcurrentOSplatforms,legacysystemsoftenpresentupgradeanddriverincompatibilityissues.
Q: What are the primary advantages of Vicom’s
migration approach?
Whilehost‐basedmigrationprovidessomeadvantages,manyofthesetendtobeoffsetbyimplementationandoperatingconsiderations,especiallyasthescaleofmigrationsandnumberofserverplatformsincrease.Inaddition,althoughout‐of‐pocketexpensesofin‐househost‐basedmigrationsmayappearsmall,thecostofITresourcescanaddupquickly.Byundertakingamigrationproject,ITassumesallresponsibilityandriskforon‐timeprojectdelivery.Moreover,latemigrationdeliveriescanalsoaddsignificantlytoleasedstoragecostsandadverselyaffectbusinessoperations.Accordingtoa2005surveyofover200ITmanagersbytheEnterpriseStorageGroupandInfoStorMagazine,83percentofinternalmigrationprojectsexceedplannedstafftime,61percentrequiremoredowntimethanexpected,and54percentareoverbudget.VicomAdvantages:ExperienceandTechnology
Vicom’stechnology,automation,provenprocesses,andspecialist‐backedserviceseliminatemuchofthecomplexityandlaborassociatedwith
Server
SAN
Figure2.Host‐BasedMigration
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migrations.Vicomdeliversdatamigrationsfaster,withfewerproblems,andzerooperatingrisk.And,withtheexceptionofcustomizedmigrations,Vicomalsoprovidesamoney‐backguaranteeforon‐timecompletionofeachofitsmigrations.
AdvantagesofVicommigrationsoverin‐house,host‐basedmethodsinclude:
• Automateddiscoveryandconfigurationverificationthateliminateslaborandhumanerrorassociatedwithmanualmigrationmanagement.
• SANvirtualizationtechnologythateliminatesSANcompatibilityissuesandtheneedforsoftwareanddriverinstallationonhostsystems,savingtimeandlabor.
• Afast,independentdata‐movingappliancethatmigratesdataatmuchhigherratesthanpossiblewithhost‐powereddatamigrations.Typically,theVicomapplianceinMaxSpeedmodemigratesdataat600GBto1TBperhourcomparedto100GBperhourorlessforhost‐poweredmigrations.
• Guaranteedfallbacktooriginalsystemoperationintheunlikelyeventthatissuesariseduringamigration.
• Provenmigrationprocessesdevelopedinthedeliveryofover500enterprisemigrations.
• Experiencedmigrationspecialistswhohavedeliveredmigrationsinabroadrangeofenvironments,configurations,andoperatingcircumstances.Thisincludeslegacy/mixedplatformandmixedfabricenvironments,clusteredservers,bootLUN,LUNconsolidation,andcontinuousavailabilityoperations.
• Aone‐stop,solution‐orientedmigrationservicethatnotonlyuseshighlyefficientVicommigrationappliancetechnology,software,andprocesses,butalsobest‐of‐breedthird‐partysoftwaretoolstosatisfyuniquemigrationrequirements.Ourrepertoireincludeshost‐basedmethodsandsoftware.WemigratebothSANandNASdata.WithVicom,youhaveacost‐effective,single‐vendormigrationproviderregardlessofconfigurationoroperatingneeds.
Example:LaborComparisonBetweenInHouseandVicomMigrations
IncomparingVicom’sapproachwithin‐housemigrationprojects,itiseasytoseewhyVicomholdsmorethana3:1advantageinlaborandtimerequired.Mostcompaniesareconfrontedwiththeneedtoperformlarge‐scaledatamigrationsonlywhenastoragetechnologyrefreshisrequired.Asaresult,mostITstaffsarerelativelyinexperiencedatdeliveringcomplexmigrations.Often,theyhaveonlybasicprocessesestablishedforplanning,coordinatingserverandstorageavailabilities,andmigratingdata.Forthesamereason,migrationtoolsandexperienceinusingthemaretheexceptionratherthantherule.Bycomparison,aVicommigrationspecialistsperformmigrationseveryweek.Provenprocessesarefollowedoneverymigration,whiletoolsandsoftwareeliminatemuchofthelaborandneedfortroubleshootingassociatedwithmanualmigrations.
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Toshowhowthesedifferencesaffecttheimplementationandcompletionofamigrationproject,Table2comparestheestimatedlaborfora10‐terabyte/10‐server,in‐househost‐basedmigrationconfiguredforonlineoperationwiththelaborforanequivalentonlineContinuousmigrationusingaVicommigrationappliance.
Asshownbythiscomparison,thein‐house,on‐linemigrationrequiresalmostthreetimesthelaborneededforaContinousmigrationusingtheVicomappliance.Incontrast,aVicomMaxspeedofflinemigrationwouldbeabout25percentmoreefficientthantheContinuousmethod,resultingina4:1Vicomadvantage.(Note:thecomparisondoesnotincludetimespentinreplicatingdatawhileonline,whichwillberoughlythesameforhost‐basedandVicommethods.)
Amongthesevenindividualmigrationstepsshown,Vicomholdsalaboradvantageof2:1to40:1.And,whileVicomtechnologymakesabigdifference,ourexperienceshowsthatoneofthebiggesttime‐saversistheVicommigrationplanningprocess,whichisbuiltoninformationacquiredfromVicomtoolsanddocumentation.
Q: Who are your customers?
VicommigrationcustomersrunthegamutfromFortune1000tosmallandmediumenterprisesacrossarangeofindustries.Throughdirectservicesandservicepartnerships,Vicomhassuccessfullydeliveredover500datamigrationsandmovedoverfivepetabytesofdataindiverseenterpriseenvironments.Selectedcustomersarelistedbelow.ReferencesareavailableuponrequestfromVicomSystems.
Avaya Goody’sClothing ScientificLearningBloomberg Heinz SiemensBlueCross HealthFirst SiriusSatelliteCaterpillarTractor Intelsat SouthernCompanyComcast MCGHealth StateFarmInsuranceDCMA(U.S.Gov’t) Pepsico TexasLegislativeCouncil
Table 2. Labor Comparison for Host-Based vs. Vicom Appliance-Based Migration
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DeutscheBank Prudential TorayPlasticsDialAmerica ReedBusiness TimkenEsurance RoperSt.FrancisHealth UnileverFruitoftheLoom RoyalCaribbean WellsFargo
Q: How do Vicom’s MaxSpeed and Continuous Migration methods compare in:
• Migration speed?
• System availability?
• Time to completion? Vicom’sMaxSpeedmigrationsareperformedduringplannedoutageperiodswhenserversmaybetakenoffline.Duringtheseperiods,themigrationappliancereplicatesdatafromsourcetonewstoragesystematmaximumavailableI/Obandwidths.However,undersomecircumstancessuchase‐commerce,operatingrequirementsmayseverelyrestricttheperiodinwhichhostserverscanremainoffline.Intheseinstances,itmaybemoreeffectivetouseaContinuousmigrationmethodinwhichdataismigratedinthebackgroundwhilethehostserversremainonline.Figure3illustrateshowthesetwomethodscompareinserveroutagewindowsandtimerequiredtoperformthemigrations.
Figure3.MaxSpeedvs.ContinuousMigration
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Table1belowfurtherillustateshowthetwomethodsdifferinmigrationspeed,serveravailability,andmigrationcompletiontimes.
Timeandspeed‐wise,MaxSpeedmigrationsaremuchfasterthanContinuousalternatives,especiallyasthenumberofserversincreases.ThisisduetothespeedadvantageofVicom’smigrationapplianceandefficiencyoftheMaxSpeedmigrationmethod.Forthetypicalmid‐sizemigrationof5‐30terabytesand10‐20servers,MaxSpeedmigrationscanbecompletedabout4timesfasterthanContinuousmigrations.
InlargeSANstoragemigrations,wheretherearebusiness‐criticalandnon‐businesscriticalavailabilityrequirements,VicomusesbothMaxSpeedandContinuousmigrationmethods.Typically,Maxspeedmigrationisusedtomigratethemajorityofdataquicklyandefficiently,whileContinuousmigrationisreservedforbusiness‐criticalapplications.Thiscombinedapproachproducesacost‐effectiveresult,whilealsosatisfyinghigh‐availabilityoperatingneeds.
Q: How Does Vicom Ensure Migration Data Integrity? Toensuremigrationdataintegritywhilealsomeetingoperatingconstraints,VicomSystemsemploysamulti‐leveldataverificationmethodthathasbeenusedinover500enterprisemigrationswitha100‐percentsuccessrate.Infact,inmigratingoverfivepetabytesofdata,notasinglebyteofdatahaseverbeenlostorcorrupted.Toachievethis,Vicomemploysacombinationofdeviceandsystem‐levelverificationthatincludes:• SAN‐level,error‐correctionlogicbuiltintoVicom’smigrationappliance• SAN‐levelerror‐logging• LUNintegritychecks• Filesystemandapplicationchecks
Table1.MaxSpeedvs.ContinuousMigrationSpeeds
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SANlevelErrorCorrection
TheVicommigrationapplianceisdesignedforextremelyreliableSANdatareplicationatFibreChannelspeed.Inreplicatingdata,allsourcestoragedataremainsintactduringandaftermigration,providingafail‐safefallbackalternativeintheunlikelyeventofadatamigrationproblem.Throughembeddedhardwaredesign,allmigrateddataissubjectedtoerrorcheckingandsingleanddouble‐biterrorsaredetectedonthefly.Replicationalsorequiresthatdatamustbeverifiedbeforeitcanbewrittentothenewsystem.Error‐correctionandreplicationbytheVicomappliance,combinedwithhighlyreliableSCSI/FCprotocol,producestheequivalentofdirectRAID1mirroringbetweenthesourceandnewstoragesystem.Ineffect,theVicomapplianceactsasadedicatedRAIDcontrollerthatcreatesamirroredcopyofthesourcedata—asimplerandmorereliablemethodthanhost‐basedcopymethodsofdatamigration.
SANlevelExceptionLogging
TheVicomappliancemonitorstheentiredatamigrationandlogsanyexceptionsreportedduringtheoperation.Whenreported,abnormallevelsofexceptionhandlingmayindicatepotentialdataintegrityproblems.Vicomstandardprocedurescallformigrationspecialiststoreviewexceptionlogs,and,ifproblemsareidentified,torepeatthemigrationfortheproblematicLUN.LUNIntegrityChecks
Followingmigration,thefirstandlastdatablocksofeachnewLUNarecomparedwithdatablocksinthesourceLUN.FileSystemandApplicationChecks
Thefinalverificationstepfollowingmigrationconsistsof100‐percentfilesystemconsistencycheck(FSCK)ofdatavolumesand100‐percentapplicationlaunchtest.Ingeneral,customerITstaffshavepreferredtoperformthissetoftestsasameansoffirst‐handmigrationverification,aidedbytheVicommigrationspecialistasrequired.
Figure4.DataIntegrityChecks
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Asmentionedatthebeginningofthisnote,Vicomhasmigratedoverfivepetabyteswithoutaninstanceoflossorcorruptionofasinglebyteofdata.Thisincludesthemigrationofover100,000LUNs.Basedonactualperformance,webelievetheefficacyofbothVicommigrationtechnologyanddata
www.vicom.com
Copyright 2009, Vicom Systems, Inc. All rights reserved. Vicom Systems, Vicom DMS, and MaxSpeed are trademarks of Vicom Systems, Inc. Other company and product names mentioned herein are trademarks of their respective companies. December 2008. V010809.