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Transcript of Deciding Where to Deploy Solid-State Storage Devices_hb_final
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Drill Down
1EDITORS NOTE
2FOUR USE CASES WHEN SSD ARRAYS ARE THE RIGHT SOLUTION
3FIND THE BEST SPOT FOR FLASH SSD STORAGE
4WHEN USING SSD IS A BAD IDEA
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Deciding Where to Deploy Solid-State Storage DevicesSolid state storage can be deployed in a storage array alongside traditional hard disk drives, as an all-flash array, as a separate caching appliance, or in the a server using a PCIe card. Each approach has pros and cons which must be weighed before deploying a solution.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
2 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
1EDITORS NOTE Where to Deploy Flash
Enterprise-class flash storage iskindofatechWildWestrightnow.Theresalotgoingonandthetechnologyisnotfullymatured.Standardsareemergingnow,butthereisalotofproprietarystuffonthemarket,manyofthevendorsaresmallstart-upsthatmayfailorbeboughtbybiggerstoragecompa-nies,andthereareanumberofplacesyoucandeployflasheachwithitsownbenefitsanddrawbacks.Youcantdomuchaboutthefirsttwoissues
excepttowaitforthingstoshakeout.However,youcanandshouldbestrategicaboutwhereyoudeployflashinyourenvironment.Probablythemostobviouswaytodeploy
flashisusinganHDDformfactorsolid-statedrive.Theseareusedinsomestoragearraystodaythesecanbeall-flasharraysorhybridarrayswithflashalongsidetraditionalhard
drives.AnotheroptionistouseHDDformfactorflashSSDsasTier0storageinamulti-tierNASorstoragearray.Youcanalsodeployflashinacacheappliancethatsitsinfrontofanexistingstoragearray.TheseappliancesmayemployPCIeorHDDformfactorflash.Finally,youcandeployPCIeflashSSDstoragecardsascacheorstorageintheserver,orascacheinastoragesystem.InthisDrillDownonwheretodeploysolid-
statestorage,discovertheprosandconsofalltheseoptions,effectiveusecasesforsolid-statestorage,andexamplesofwhenflashisnottherighttoolforthejob.Ifyouareconsideringinvestinginsolidstatestorage,thisDrillDownisgreatplacetostart.n
Andrew BurtonSenior Site Editor, SearchSolidStateStorage.com
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
3 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
2FOUR USE CASES Four Use Cases When SSD Arrays Are the Right Solution
SSD arrays are oftencalledTier0,SSDtier,orcachetier.AnSSDarraysolvestheI/Oproblemofaggregatethroughputwithoutre-sortingtomassivenumbersofspindlesandin-efficientlypopulatedHDDs.All-SSDstoragearraysareoftenoverlooked
intheirownright.Thesestandalonedevicesprovideadditionalbenefits,suchasoptimizeddatalocationandtheflexibilityofdevice-independentdeployment.Theydoaddagroupofdevicestobemanaged,sothebenefitsmustoutweightheaddedadministrationandmain-tenance.HerearefourusecaseswhereanSSDarraymightbejusttherightsolution.
nUse case #1: Front end-virtualized for inter-nal cloud storage.Organizationsreducecostsbyincreasinglyusinglower-costTier3(SATA)storage,especiallyforinternalclouds.Unfor-tunately,thethroughputofthesehigh-capac-ity,low-performancedrivesmaynotdeliver
sufficientI/O.Inthesesituations,ITman-agersshouldconsidersolid-statearraysandautomated-tieringsoftwaretomanagethedatamovementbetweentiers.
nUse case #2: Data location for file services.GlobalorganizationsusingcommonfilestocollaboratecanuseSSDarraystopositionthedatageographicallyorsimplyelevateittothefastesttierformaximumthroughput.Largefilestypicallyusedingeographicdispersedcol-laborationthatwouldgreatlybenefitfromSSDaccelerationincludeengineeringdocumentsorvideodevelopmentfiles.ForInternetcontentproviders,thismayincludevideofiles,musicfilesorotherdownloads.
nUse case #3: VDI boot storms.Manyorga-nizationsbootvirtualdesktopinfrastructure(VDI)serversfromnetworkstoragetoensureacommonimage,aswellassimplifyupdatesand
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
4 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
2FOUR USE CASES maintenance.WithstandardHDDarrays,theresultingtrafficjamduringrushhoursyieldssufficientlypoorperformancethatsomeorga-nizationsshiedawayfromthepractice.SSDsexceptionalrecursivereadperformancemakesitaperfectwaytobeatthebootstorm.
nUse case #4: Hybrid cloud.Hostinginfre-quentlyusedinformationonpubliccloudstor-agecanbeanexcellentwaytoreducethecostofmaintainingthisdata.However,thelatencyofthisconfigurationmaybeunacceptable.BypositioninganSSDarrayinthehomedatacen-tertocachehotdatafromtheremotecloud,ITorganizationscanhavethebestofbothworldson-premiseshigh-performancestor-ageandmassivestoragecapacityoffsite.Ofcourse,thenetworkinterconnectrequiresre-dundancytoensurefullavailability.Inallimplementations,SSDsolvesthe
I/Odata-deliveryproblem.Thetricktoget-tingthedesiredresultsisdeterminingexactlywherethatproblemexists.Moreover,simplyincreasingaggregatedatathroughputwithoutconsideringpossiblecountervailinglatencyin-troducedbynetworkconnectionsmayresultinalotofmoneyspentwithoutalotofgain.IfthepotentialusesofTier0andSSDarrays
soundsimilar,theyare.Thedifferencebetweenthemisdatalocation.Whendevicesarewithinthesamedatacenter,Tier0islikelytofulfilltherequirementswithoutaddingmoredevicestomanage.WhileSSDarrayscanalsomeettheperformancerequirementswithindatacenters,theyaremostapplicableforfacilitatingrapiddataaccesswhendevicesaregeographicallydi-verse.So,itboilsdowntotwoconsiderations:timeanddistance.Addressthosetwoconsider-ationsandyoureonthewaytotherightdeci-sion.Phil Goodwin
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
5 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD Find the Best Spot for Flash SSD Storage
There are six differentflashSSDstor-ageimplementationstoday.Eachisprimarilyaimedatreducinglatency,improvingperfor-manceinIOPSandthroughput,whilesecond-arilyaimedatreducingstoragetotalcostofownership(TCO).
PCIE FLASH CARDS AS SERVER CACHE OR STORAGEPuttingtheflashSSDPCIecardlocallyintheserveronthePCIebusputsthecacheclosertotheapplication.Therearenoadapters,trans-ceivers,networkcables,switchesorstoragecontrollersinthepath.Theshortdistancere-duceslatency,speedingupallI/Ooperations.Thisiswhythesecardsaretypicallycalledapplicationacceleratorsinsteadofstorageac-celerators.ThistypeofflashSSDisprimarilyblock-based.Whenusedascache,itrequiresadditionalsoftwarethatreliesuponpoliciesto
movedataintoandoutofthecache,suchasfirst-in,first-out.
nPros:Lowestlatenciesbetweenapplicationsandstorageorstoragecaching.Makesasig-nificant,noticeableandquantifiabledifferenceforhigh-transactionalandhigh-performanceapplications,suchasonlinetransactionpro-cessing(OLTP),onlineanalyticalprocessing(OLAP),graphicsrendering,genomeprocessingandproteinanalysis.
nCons:HighCPUresourceuse,rangingfrom5%to25%.Ithasrelativelylowcapacities,althoughtheFusion-ioInc.ioDriveOctalhas10TBpercardinadouble-widePCIedevice.Cardsarenotshareableamongmultiplephysi-calserverswithoutadditionaloptionssuchasSanDiskCorp.sFlashSoftcachingsoftwareorQLogicCorp.sFabricCacheQLE10000FibreChannelhostbusadapter.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
6 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD Eachphysicalserverrequiresoneormorecards.Notusefulforvirtualserversexceptascachewithcachingsoftwarebecausevirtualmachine(VM)portabilityandresiliencere-quiressharedstorage.Cachingsoftwarelicens-ingisonaper-physical-serverbasis.Mostofthecachingsoftwareisblockstorage,makingitsomewhatuselessinfilebasedstorageorappli-cations.IntelCorp.sIntelCacheAccelerationSoftwareistheexception.Cardmanagementisonaper-cardbasis,increasingadministratormanagementtasksresultinginahighTCO.
nBest fits:Well-suitedforhigh-performancecomputingclusterswhereperformanceim-provementsinnanosecondstomicrosecondsarehuge.OthersolidfitsincludeOLTP,OLAP,businessintelligence,socialmedia,genomeprocessing,proteinprocessing,graphicsren-dering,security,facialrecognitionandseismicprocessing.
PCIE FLASH CARDS AS SAN OR NAS CACHEPCIeflashSSDstoragecardsprovidestor-agesystemsalower-cost,higher-capacity
andslightlyless-performingextensionofthesystemsDRAM.Itsastorageaccelerator.Al-gorithmsdeterminelessfrequentlyaccesseddata,whichisquicklymovedfromthesystemsDRAMtotheflashPCIeSSDcache.ThePCIeSSDcacheactsasanextensionoftheDRAM.Administratorssetpoliciesforthesecaches,
determiningwhattypeofdatashouldbere-tainedorpinnedinflashcache(datanotevictedfromthecache).TheuseofPCIeflashSSDsascachereduceslatencytoandfromthestoragesystembyreducingdiskI/Owhensat-isfyingreadrequestsand,inthecaseofNAS,metadataaswell.
nPros:Reduceslatenciesfromapplicationstosharedstorage.Itworkswellwithvirtualserv-ers,virtualdesktopinfrastructure(VDI),VMportability,andVMresilience.Itsshareableamongphysicalandvirtualserversandrequiresnoserverresources.
nCons:Flashcacheissize-limitedbyavailablestoragesystemPCIeslots.Usersexperiencein-creasedlatenciesandexcessiveresponsetimesbecausemorefrequentcachemissesrequire
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
7 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD requeststogetthedatafromtheHDDs.Anygivenstoragesystemsflashcachecannotbesharedbyanyotherstoragesystemwithoutseparatephysicalorsoftwaresolutions.ThemostsevereperformancebottleneckismostoftenthestoragesystemsCPU.AsCPUuti-lizationelevates,sodoeslatencyanduserre-sponsetimes.UsingaPCIeSSDasaSANorNAScachetendstohaveanexpensiveTCO.
nBest fits:Well-suitedforvirtualserversandVDI.Goodatprovidingaboosttoheavytraf-ficapplicationssuchasMicrosoftExchange.Itdoeswellatacceleratingdatabaseswhenin-dexesandhotfilescanbepinnedtothecache.
SSD FLASH AS STORAGE ARRAY CACHEHDDformfactorflashSSDstoragecacheisfunctionallysimilartoPCIeflashSSDstorageascache.Itsastorageacceleratorwithsimilaralgorithms.InsteadofgoingintothecontrollerasPCIeSSDcardsdo,HDDformfactorSSDsgobehindthestoragecontrollerinHDDslots.Sittingbehindthecontrollermeanshigherca-pacitiesbuthigherlatencies.
nPros:Reduceslatencyfromapplicationstosharedstorage.Workswellwithvirtualservers,VMportability,andVMresilience.Itsshare-ableamongmultiplephysicalandvirtualserv-erswhileconsumingnoserverresources.IthaslowerTCOperGBthanthePCIeformfactor.
nCons:CapacitiesarelargerthanPCIeflashSSDs,butlimitedbybothflashSSDcapacitiesanddisk-controllerperformancelimitations.Usersexperienceincreasedlatenciesandexces-siveresponsetimesbecausecachemissesoc-curmorefrequently,redirectingrequeststotheHDDs.Astoragesystemsflashcachecannotbesharedbyanyotherstoragesystemwithoutseparatephysicalorsoftwaresolutions.Themostsevereperformancebottleneckiscom-monlythestoragecontroller,whichincreaseslatencyanduserresponsetimes.
nBest fits:Well-suitedforvirtualserversandVDI.Goodatprovidingaboosttovirtualenvi-ronmentsandheavytrafficapplications,suchasMicrosoftExchange.Itdoesagoodjobatac-celeratingdatabaseswhenindexesandhotfilescanbepinnedtothecache.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
8 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD SSD FLASH AS TIER 0 STORAGETier0storageissimilartoHDDformfactorflashSSDstorageascache.ThedifferenceisinhowtheHDDformfactorflashSSDistreated.Itmakesflashfunctionasthehigh-perfor-mancestoragetierorthestoragelocationforthehottestaccesseddata.Itisalsodesignatedasthetargetfordataassociatedwithapplica-tionsrequiringveryquickresponsetimesandlowlatency.AsthedataonTier0agesandac-cessbecomeslessfrequent,auto-tieringsoft-waremovesthedatatoalower-performing,lower-costHDDstoragetier.
nPros:Reduceslatenciesfromapplicationstosharedstorage.Itworkswellwithvirtualservers,VMportabilityandVMresilience.Itsshareableamongmultiplephysicalandvirtualservers.Itrequiresnoserverresources.IthaslowerTCOperGBthanthePCIeformfactor.Itcanredistributeworkloadsinamannerthatre-ducesthetotalnumberofHDDswithoutcom-promisingperformanceorcapacity.CapacityisshiftedtoslowerhighercapacityHDDswhileperformancerequirementsarepointedatTier0HDDformfactorflashSSDs.
nCons:CapacitiesarelimitedsimilarlytoHDDformfactorflashSSDcache.Aswork-ingsetsgrowalongwithgeneraldatagrowth,thereisdiminishingabilityforthatlimitedTier0tokeepupwithdemand.Moreapplica-tionsanduserswillbepointedatslowerstor-agetiers.Usersexperienceincreasedlatenciesandexcessiveresponsetimes.Similartootherimplementations,HDDformfactorflashSSDsonlybenefitthestoragesysteminwhichtheyareinstalled.Themostsevereperformancebottleneckiscommonlythestoragecontrol-ler,increasinglatencyanduserresponsetimes.Auto-tieringsoftware,whichcanbecostly,addstothestoragesystemscontrollerutiliza-tionload,furtherimpingingonperformance.Auto-tieringsoftwaretendstomovedataonlyinadownwarddirection(DellCorp.sCompel-lentAutomaticTieredandX-IOTechnologiesHyperISEaredistinctexceptions).
nBest fits:Well-suitedforvirtualserversandVDI.GoodatprovidingaboosttoheavytrafficapplicationssuchasMicrosoftExchange.TheyaregoodatacceleratingdatabaseswhereindexesandhotfilesarenevermovedoutofTier0.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
9 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD SSD FLASH AS ALL-SSD ARRAYImplementingapure-HDDformfactorall-flashSSDstoragesystemprovidesmuchlowerlatencies,andhigherIOPSandthroughputwhileeliminatingcachingortieringrequire-ments.All-SSDstoragesystemshaveenor-mousperformanceandsimplicityappeal.MostleverageSSDperformancetoincludesomeformofdatareduction,suchasdeduplicationandlosslesscompression.Systemandflashspeedarefastenoughthatapplicationsandus-erstypicallydontnoticetheadditionaldatareductionlatency.
nPros:Reduceslatenciesfromapplicationstosharedstorage.Havingonlyonestoragetiereliminatescomplicatedstoragetieringsoft-ware.Workswellwithvirtualservers,VMportability,andVMresilienceandshareableamongmultiplephysicalandvirtualserv-ers,consumingnoserverresources.HDD
eliminationprominentlyreducespowerandcooling.Combiningpowerandcoolingsavingswithdatareductioncapacitysavingsprovidesanet-effectiveGBTCOinlinewithmanyHDDstoragesystems,whereascostperIOPSorthroughputisconspicuouslybetter.
nCons:Scalabilitytendstobelimitedtolessthan500TBrawstorageandsomecases,muchless(SolidFireInc.sstoragesystemisanexcep-tionthatscalestoapetabyteofrawstorage).Thebottleneckwiththistypeofstoragesystemisthestoragecontrollerutilization.Ascontrol-lerutilizationelevates,sodoeslatencyanduserresponsetimes.
nBest fits:Well-suitedforvirtualserverandVDIenvironments.Goodatprovidingaboosttovirtualenvironmentsandheavytrafficap-plicationssuchasMicrosoftExchange.Itdoesagoodjobatacceleratingdatabases.Any
Implementing a pure-HDD form factor all-flash SSD storage system provides much lower latencies, and higher IOPS and throughput while eliminating caching or tiering requirements.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
10 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD applicationrequiringalotofperformanceandcapacitythatsmorethancanbefoundineithercachingortieringisagoodfit.Datacenterswithlimitedpowerandcoolingavailabilityarealsoagoodfit.
PCIE CARDS OR SSD FLASH IN A NETWORKED CACHING APPLIANCECachingappliancessitnon-disruptivelyonthestoragenetworklogicallybetweenclientsandthestoragesystems.Cachingappliancesareprimarilyreadand
metadataforNASonly.TheyareloadedupwitheitherPCIeflashcardSSDsorHDDformfactorSSDs.Capacitiestendtobelessthan30TB.Theseappliancesarepurpose-builtforcaching.Therearefourdifferenttypesofcaching
appliances:
1.Dumb(severelylimitedstoragesystemsoftwaresuchassnapshot,thinprovi-sioning,datareduction,replication,etc.)non-appawareblock-basedaccelerationap-proach(ViolinMemoryInc.,TexasMemory
Systems(nowIBM),EMCCorp.Thunder,andAstuteNetworksInc.).
2.File-baseddumbnon-appawarevariation(AvereSystemsInc.).
3.IPnetworkintelligentpacketinspectionthatcachesappropriatedatatotheappli-ance(CacheIQ,nowpartofNetAppInc.).
4.File-basedapplicationreadandmetadataaccelerationcachingappliance(AlacritechInc.sANX1500accelerationapplianceandNetAppsStorageAccelerationappli-ances).Filesarestoredontheappliancebasedonreadfrequency.Asfrequencydeclines,theyreremoved.Metadataisalsokeptontheappliance.Typically,thistypeofcachingproducesthelowestfilelatencies.
nPros:Reduceslatenciesfromapplicationstosharedstorage.Cachingappliancesarethemostleverageableandshareablewithphysi-calservers,virtualserversandmultiplestoragesystems.Thefile-basedapplicationreadand
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
1 1 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
3BEST SPOT FOR FLASH SSD metadataaccelerationapproachreducesNFSandTCP/IPlatencies,makingboththereadsandmetadataalotfaster.Alltheappliancetypesreducecontroller
loadontheback-endstoragesystems,enablingmoreback-endstoragecontrollercyclesformodern-daystoragefunctions,whichimpro-vesoverallperformance.TCOtendstobethelowestwiththistypeofflashSSDwhilethecostperIOPSorthroughputisequivalent.
nCons:Scalabilitytendstobelessthan10TBrawstorageinsomecases.Itisanothersystemthatsitsbetweenserversandstorage,making
troubleshootingabitmorecomplicated.Forfilecaching,itworksbetterwithNFSthanCIFS.
nBest fits:Well-suitedforvirtualserverandVDI.IdealforloweringoverallstoragecostswhileincreasingIOPSandthroughput.GoodfitforHPC(block),rendering(file),genomeandproteinsequencing.
Onefinalnote:Onesizeortypeofflashstor-agedoesnotfitall.Bepreparedtoimplementdifferentflashstoragevariationstosolvedif-ferentproblemsandapplicationrequirements. Marc Staimer
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
12 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
4BAD SOLID-STATE STORAGE USES When Using SSD Is a Bad Idea
Solid-state storage (SSS) hasestab-lisheditspositioninthedatacenter.NearlyallmajorvendorsspecifyaTier0intheirbest-practicearchitectures.Companiesareusingserver-sidesolid-statedisks(SSDs)toenhanceserverperformance,andstorage-sideSSDseliminatesboot-stormbottlenecks.Aswithmosttechnologies,itsasimportanttoknowwhennottouseitasitiswhentouseit.Herearesomecaseswherenottousesolid-statestorage.
nDont use SSS when applications are not read-intensive.Solid-statestorageisbrilliantforread-accesstimes.ItcanoutperformHDDby10Xormore.Thereisnofreelunch,how-ever,asSSSlosesallitsbenefitsinthewritecategory.Writesnotonlylag,theyalsowearouttheSSSmemorycells.Memorycellshaveanaveragewritelifeafterwhichthecellsbegintoburnout(seeyourvendorfordetailsofits
specificsystem).Ascellsfail,overallperfor-mancedegrades.Eventually,theSSSmustbereplacedtorestorefullperformanceandweallknowSSSisnotcheap.Somevendorsdoofferextensivewarranties.Sowhatisthemagiclineforaread/write
ratio?Thereprobablyisntone,butstartwith90/10asideal.Applicationrequirementsmaydictateacompromiseinthisregard,butknow-ingpermitsITmanagerstomakeaconsciousdecision.Iftheratioisbelow50/50,thenobvi-ouslyanHDDwouldbeabetterchoice.Here,fromanapplicationperformanceper-
spective,theSSSreadperformanceisoffsetbytheinferiorwriteperformance.Finally,ifSSSisneededforreadperformance
butwritesareanissue,considersomeofthevendorsthatemploywear-levelingmecha-nismsandminimizewrite-amplificationtoreducetheimpact.Solid-statestoragesizeisalsoafactor.GoingcheapontheSSSincreases
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
13 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
4BAD SOLID-STATE STORAGE USES thrashingasitreducesthechancesofarecur-siveread.
nDont use SSS when data access is highly random. SSSissometimereferredtoascache-tierandthenameisapropos.Fundamentally,itisacachethateliminatestheneedtoper-formafetchtoahard-drivewhenthedataiscache-resident.Applicationswithhighlyran-domaccessrequirementssimplywontbenefitfromSSSthearraycontrollerdirectsthereadtotheHDDandtheSSSbecomesanexpensewithlittlebenefit.
nDont use general-purpose SSS in highly virtualized environments.OK,thisonewillgeneratesomecontroversybecausetherearesomereallygoodusecasesforSSSwithvirtualmachines(VMs),suchasbootstorms.However,manyVMsaccessingthesameSSSresultsinhighlyrandomdatapatterns,atleastfromasto-rageperspective.WhenhundredsofVMsare
readingandwritingfromthesamestorage,onemachineisconstantlyover-writingtheother.However,thereareSSSsolutionsdesignedspe-cificallyforvirtualenvironments,whichiswhytheresageneralpurposecaveat.
nDont use server-side SSS for solving storage I/O bottlenecks. Server-sideSSSisfundamen-tallyservercache,whichsolvesaprocessingproblemandevenanetworkbandwidthprob-lem.SpreadingSSSacrosshundredsofphysi-calservers,equippingeachserverwithitsownSSS,mayindeedhelpwithI/Obottlenecks,butitsnotnearlyaseffectiveasthesameaggre-gatecapacityinastoragetier.
nDont use Tier 0 for solving network bottle-necks.Ifthenetworkinhibitsdatadelivery,itsobviousthatoptimizingthestoragesystembe-hindthenetworkdoeslittlegood.Server-sideSSSmayreducetheneedtoaccessthestoragesystemandreducethenetworkdemand.
If the network inhibits data delivery, its obvious that optimizing the storage system behind the network does little good.
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
14 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
4BAD SOLID-STATE STORAGE USES nDont deploy consumer-grade SSS for enterprise applications. SSDismanufacturedinfourgrades:single-layercell(SLC),multi-layercell(MLC),enterprisemulti-layercell(eMLC)andtriple-layercell(TLC).MLCisconsideredconsumer-gradeflashandfoundinmostoff-the-shelfapplications.Ithasalifespanof3,000-10,000writeoperationspercell.TLCisalsoconsideredconsumer-gradeflash,
butitslifespanisevenshorterthanMLC,withonly800to1,000writeoperationspercell.SLC,orenterprise-grade,hasalifeofupto100,000writeoperationspercell.eMLCattemptstostrikeabalancebetweenpriceandperformance,offeringaround30,000writespercellbutatalowerpricepointthanSLC.Caveatemptor,asyougetwhatyoupayfor. Phil Goodwin
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Home
Editors Note
Four Use Cases When SSD Arrays
Are the Right Solution
Find the Best Spot for Flash SSD Storage
When Using SSD Is a Bad Idea
15 DEC ID ING WHERE TO DEPLOY SOL ID-STATE STORAGE DEVICES
PHIL GOODWIN is a storage consultant and freelance writer.
MARC STAIMER is the founder, senior analyst and CDS of Dragon Slayer Consulting in Beaverton, Ore. Marc can be contacted at [email protected].
ABOUT THE
AUTHORS
Deciding Where to Deploy Solid-State Storage DevicesisaSearchSolidStateStorage.come-publication.
Rich Castagna | Editorial Director
Andrew Burton | Senior Site Editor
Ed Hannan | Managing Editor
John Hilliard | Associate Site Editor
Todd Erickson | Features Writer
Linda Koury | Director of Online Design
Neva Maniscalco | Graphic Designer
Jillian Abbott | Publisher [email protected]
TechTarget 275GroveStreet,Newton,MA02466
www.techtarget.com
2013TechTargetInc.Nopartofthispublicationmaybetransmittedorre-producedinanyformorbyanymeanswithoutwrittenpermissionfromthepublisher.TechTargetreprintsareavailablethroughTheYGSGroup.
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