Definition阵列卡
阵列卡 时间:2021-03-28 阅读:()
1Copyright2015EMCCorporation.
Allrightsreserved.
RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresPresenter:AoMaAjointworkwithFredDouglis,GuanlinLu,DarrenSawyerSurendarChandra,WindsorHsu2Copyright2015EMCCorporation.
Allrightsreserved.
DiskfailuresarecommonplaceWhole-diskfailurePartialfailureRAIDiswidelydeployedProtectdataagainstfailureswithredundancyPervasiveRAIDProtection3Copyright2015EMCCorporation.
Allrightsreserved.
StoragesystemisevolvingEscalateduseoflessreliabledrivescausesmorewhole-diskfailuresIncreasingdiskcapacityresultsinmoresectorerrorsSolutionAddextraredundancy(RAID5,RAID6,…)–EnsuredatareliabilityatthecostofstorageefficiencyRAIDOverviewIsaddingextraredundancyanefficientsolution4Copyright2015EMCCorporation.
Allrightsreserved.
Analyzed1millionSATAdisksandrevealedFailuremodesdegradingRAIDreliabilityReallocatedsectorsreflectdiskreliabilitydeteriorationDiskfailureispredictableBuiltRAIDSHIELD,anactivedefensemechanismReconstructfailingdiskbeforeit'stoolate!
PLATE:single-diskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroupsWhatWeDid5Copyright2015EMCCorporation.
Allrightsreserved.
BackgroundDiskfailureanalysisRAIDSHIELD:IdentifyfailureindicatorReallocatedSector(RS)characterizationSinglediskproactiveprotectionDiskgroupproactiveprotection5Outline6Copyright2015EMCCorporation.
Allrightsreserved.
Diskfailuredoesnotfollowafail-stopmodelTheproductionsystemsstudieddefinefailureasConnectionislostAnoperationexceedsthetimeoutthresholdWritefailsWhole-diskFailureDefinition7Copyright2015EMCCorporation.
Allrightsreserved.
EachdiskdrivemodelisdenotedasRelativesizeswithinafamilyareorderedbythecapacitynumber–E.
g.
A-2islargerthanA-1DiskModelPopulation(Thousands)FirstDeploymentLogLength(Months)A-13406/200860A-216511/200860B-110006/200848C-19310/201036C-225312/201036D-138409/201121DiskDataCollection8Copyright2015EMCCorporation.
Allrightsreserved.
WhatDoRealDiskFailuresLookLike9Copyright2015EMCCorporation.
Allrightsreserved.
0001424462031010203040500-612-1824-3036-4248-54A-2MonthDistributionofLifetimeofFailedDrives001241534291130102030400-612-1824-3036-4248-54A-1MonthAlargefractionoffaileddrivesarefoundatasimilaragePercentage(%)Percentage(%)10Copyright2015EMCCorporation.
Allrightsreserved.
ThenumberofaffecteddiskskeepgrowingAbout10%ofdisksgetsectorerrorsatthe3rdyearSectorerrornumbersincreasescontinuouslyAverageerrorcountincreases25%to300%yearoveryearIncreasingFrequencyofSectorErrors11Copyright2015EMCCorporation.
Allrightsreserved.
DrivefailingatasimilarageFailurerateisnotconstantAhighriskofmultiplesimultaneousfailuresIncreasingfrequencyofsectorerrorsExacerbateriskofreconstructionfailuresPassiveRedundancyisInefficientEnsuringreliabilityintheworstcaserequiresaddingconsiderableextraredundancy,makingitunattractivefromacostperspective12Copyright2015EMCCorporation.
Allrightsreserved.
MotivationEnsuredatasafetywithminimalredundancyProactivelyrecognizeimpendingfailuresandmigratevulnerabledatainadvanceMethodologyIdentifyindicatorofimpendingfailureIndicatorcharacterizationProactiveprotectionRAIDSHIELD,TheProactiveProtection13Copyright2015EMCCorporation.
Allrightsreserved.
PotentialindicatorsVariousdiskerrorsCriteriaofagoodindicatorIthappensmuchmorefrequentlyonfaileddisksratherthanworkingdisksApproachQuantifythediscriminationbetweenerrorvalueonfaileddisksandworkingones–DecilescomparisonisusedIdentifyFailureIndicator14Copyright2015EMCCorporation.
Allrightsreserved.
FaileddiskshavemoremediaerrorsthanworkingonesThediscriminationisnotsignificantenoughMediaErrorComparison2359152232478611123471330020406080100123456789faileddiskworkingdiskDecilesA-2MediaErrorCount15Copyright2015EMCCorporation.
Allrightsreserved.
2238718732752281212422025000001262905001000150020002500123456789faileddiskworkingdiskA-2DecilesReallocatedSectorCountA-2DecilesRSisstronglycorrelatedwithdiskfailuresReallocatedSector(RS)Comparison16Copyright2015EMCCorporation.
Allrightsreserved.
MostfaileddrivestendtohavealargernumberofRSthanworkingonesRSisstronglycorrelatedwithwhole-diskfailures,followedbymediaerrors,pendingsectorerrorsanduncorrectablesectorerrorsCorrelationBetweenSectorErrorsAndWhole-diskFailureRSisastrongindicatorofimpendingdiskfailure17Copyright2015EMCCorporation.
Allrightsreserved.
LargerRScountimplieshigherfailurerateintwo-monthwindowDiskFailureRateGivenDifferentRSCount1.
767758083858689909091929393949502040608010004080120160200240280320360400440480520560600DiskFailureRate(%)RScountA-2RSCharacterization(1)18Copyright2015EMCCorporation.
Allrightsreserved.
LargerRScount,fastertofail10%25%median75%90%RSCountTimeMargin(Days)DiskFailureTimeGivenDifferentRSCountRSCharacterization(2)19Copyright2015EMCCorporation.
Allrightsreserved.
RScountindicatesthedegreeofdiskreliabilitydeteriorationUsetheRScounttopredictimpendingdiskfailureinadvancePLATE:SingleDiskProactiveProtection20Copyright2015EMCCorporation.
Allrightsreserved.
70.
166.
66461.
859.
952.
14742.
63936.
94.
52.
82.
11.
71.
40.
80.
70.
40.
30.
27010203040506070809010020406080100200300400500600failurespredictedfalsepositivePercentage(%)BoththepredictedfailureandfalsepositiveratesdecreaseasthethresholdincreasesSimulationResult:FailuresCapturedRateGivenDifferentRSThresholdRSthreshold21Copyright2015EMCCorporation.
Allrightsreserved.
551515801070020406080100WithoutProactiveProtectionWithProactiveProtectionHardwareFailuresOthersTripleFailuresEliminatedTripleFailuresSingleproactiveprotectionreducesabout70%ofRAIDfailures,equivalentto88%ofthetriple-diskfailuresPLATEDeploymentResult:CausesofRecoveryIncidentsPercentage(%)22Copyright2015EMCCorporation.
Allrightsreserved.
10%remainingtriplefailuresPLATEmissesRAIDfailurescausedbymultiplelessreliabledrives,whoseRScountshaven'texceedthethresholdTriagePrioritizediskgroupswithhighestriskMotivationofARMOR:TheRAIDGroupProactiveProtection23Copyright2015EMCCorporation.
Allrightsreserved.
1-11-21-31-42-12-22-32-43-13-23-33-44-14-24-34-4XXXXThreatofFailureImminentFailureGoodDiskHealthyDG1ImminentFailureofDG2ProtectedDG3PossibleFailureofDG4Singlediskprotection:Replace2-3,2-4,3-4(PLATE)Can'tidentifyDG4northedifferencebetweenDG2andDG3Groupprotection:ReplaceDG4orincreaseredundancy(ARMOR)ProtectDG4andrecognizethedifferencebetweenDG2andDG3DiskGroupProtectionExample24Copyright2015EMCCorporation.
Allrightsreserved.
CalculatethesinglediskfailureprobabilityConditionalprobabilitythroughBayesTheoremCalculatetheprobabilityofavulnerableRAIDCombinationofthosesinglediskprobabilitiesthroughjointprobabilityARMORMethodology25Copyright2015EMCCorporation.
Allrightsreserved.
ThediscriminationshowsARMORiseffectivetorecognizeendangeredDGsInpractice,itidentifiesmostDGfailuresthatarenotpredictedbyPLATEProbabilityDecilesdistributionEvaluation0.
250.
330.
390.
440.
460.
50.
630.
730.
930.
150.
20.
230.
250.
270.
280.
30.
310.
3200.
20.
40.
60.
81123456789GroupswithmorethanonefailureGroupswithoutfailure26Copyright2015EMCCorporation.
Allrightsreserved.
GooglereportsSMARTmetricssuchasreallocatedsectorstronglysuggestanimpendingfailure,buttheyalsodeterminethathalfofthefaileddisksshownosucherrors[Pinheiro'07]DifferentworkloadandRAIDrewriteDiskfailurepredictionAveragemaximumlatency[Goldszmidt'12]SMARTfailureprediction[Murray'05,Hughes'02]RelatedWork27Copyright2015EMCCorporation.
Allrightsreserved.
Weanalyzed1millionSATAdrivesObservefailuremodesdegradingRAIDreliabilityRevealRScountreflectsthediskreliabilitydeteriorationDiskfailureispredictableWebuiltRAIDSHIELD,anactivedefensemechanismPLATE:singlediskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroups–HopetodeployinfutureIsaddingextraredundancyanefficientsolutionUseasmuchredundancyasneededtoensureavailabilityProactivereplacementshoulddecreasethelevelneededSummary28Copyright2015EMCCorporation.
Allrightsreserved.
RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresQuestionsAcknowledgementAndreaArpaci-DusseauandRemziArpaci-DusseauDataDomainengineerteam,membersofADandCTOoffice,StephenManley29Copyright2015EMCCorporation.
Allrightsreserved.
CalculatethesinglediskfailureprobabilityCalculatetheprobabilityofavulnerableRAID
Allrightsreserved.
RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresPresenter:AoMaAjointworkwithFredDouglis,GuanlinLu,DarrenSawyerSurendarChandra,WindsorHsu2Copyright2015EMCCorporation.
Allrightsreserved.
DiskfailuresarecommonplaceWhole-diskfailurePartialfailureRAIDiswidelydeployedProtectdataagainstfailureswithredundancyPervasiveRAIDProtection3Copyright2015EMCCorporation.
Allrightsreserved.
StoragesystemisevolvingEscalateduseoflessreliabledrivescausesmorewhole-diskfailuresIncreasingdiskcapacityresultsinmoresectorerrorsSolutionAddextraredundancy(RAID5,RAID6,…)–EnsuredatareliabilityatthecostofstorageefficiencyRAIDOverviewIsaddingextraredundancyanefficientsolution4Copyright2015EMCCorporation.
Allrightsreserved.
Analyzed1millionSATAdisksandrevealedFailuremodesdegradingRAIDreliabilityReallocatedsectorsreflectdiskreliabilitydeteriorationDiskfailureispredictableBuiltRAIDSHIELD,anactivedefensemechanismReconstructfailingdiskbeforeit'stoolate!
PLATE:single-diskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroupsWhatWeDid5Copyright2015EMCCorporation.
Allrightsreserved.
BackgroundDiskfailureanalysisRAIDSHIELD:IdentifyfailureindicatorReallocatedSector(RS)characterizationSinglediskproactiveprotectionDiskgroupproactiveprotection5Outline6Copyright2015EMCCorporation.
Allrightsreserved.
Diskfailuredoesnotfollowafail-stopmodelTheproductionsystemsstudieddefinefailureasConnectionislostAnoperationexceedsthetimeoutthresholdWritefailsWhole-diskFailureDefinition7Copyright2015EMCCorporation.
Allrightsreserved.
EachdiskdrivemodelisdenotedasRelativesizeswithinafamilyareorderedbythecapacitynumber–E.
g.
A-2islargerthanA-1DiskModelPopulation(Thousands)FirstDeploymentLogLength(Months)A-13406/200860A-216511/200860B-110006/200848C-19310/201036C-225312/201036D-138409/201121DiskDataCollection8Copyright2015EMCCorporation.
Allrightsreserved.
WhatDoRealDiskFailuresLookLike9Copyright2015EMCCorporation.
Allrightsreserved.
0001424462031010203040500-612-1824-3036-4248-54A-2MonthDistributionofLifetimeofFailedDrives001241534291130102030400-612-1824-3036-4248-54A-1MonthAlargefractionoffaileddrivesarefoundatasimilaragePercentage(%)Percentage(%)10Copyright2015EMCCorporation.
Allrightsreserved.
ThenumberofaffecteddiskskeepgrowingAbout10%ofdisksgetsectorerrorsatthe3rdyearSectorerrornumbersincreasescontinuouslyAverageerrorcountincreases25%to300%yearoveryearIncreasingFrequencyofSectorErrors11Copyright2015EMCCorporation.
Allrightsreserved.
DrivefailingatasimilarageFailurerateisnotconstantAhighriskofmultiplesimultaneousfailuresIncreasingfrequencyofsectorerrorsExacerbateriskofreconstructionfailuresPassiveRedundancyisInefficientEnsuringreliabilityintheworstcaserequiresaddingconsiderableextraredundancy,makingitunattractivefromacostperspective12Copyright2015EMCCorporation.
Allrightsreserved.
MotivationEnsuredatasafetywithminimalredundancyProactivelyrecognizeimpendingfailuresandmigratevulnerabledatainadvanceMethodologyIdentifyindicatorofimpendingfailureIndicatorcharacterizationProactiveprotectionRAIDSHIELD,TheProactiveProtection13Copyright2015EMCCorporation.
Allrightsreserved.
PotentialindicatorsVariousdiskerrorsCriteriaofagoodindicatorIthappensmuchmorefrequentlyonfaileddisksratherthanworkingdisksApproachQuantifythediscriminationbetweenerrorvalueonfaileddisksandworkingones–DecilescomparisonisusedIdentifyFailureIndicator14Copyright2015EMCCorporation.
Allrightsreserved.
FaileddiskshavemoremediaerrorsthanworkingonesThediscriminationisnotsignificantenoughMediaErrorComparison2359152232478611123471330020406080100123456789faileddiskworkingdiskDecilesA-2MediaErrorCount15Copyright2015EMCCorporation.
Allrightsreserved.
2238718732752281212422025000001262905001000150020002500123456789faileddiskworkingdiskA-2DecilesReallocatedSectorCountA-2DecilesRSisstronglycorrelatedwithdiskfailuresReallocatedSector(RS)Comparison16Copyright2015EMCCorporation.
Allrightsreserved.
MostfaileddrivestendtohavealargernumberofRSthanworkingonesRSisstronglycorrelatedwithwhole-diskfailures,followedbymediaerrors,pendingsectorerrorsanduncorrectablesectorerrorsCorrelationBetweenSectorErrorsAndWhole-diskFailureRSisastrongindicatorofimpendingdiskfailure17Copyright2015EMCCorporation.
Allrightsreserved.
LargerRScountimplieshigherfailurerateintwo-monthwindowDiskFailureRateGivenDifferentRSCount1.
767758083858689909091929393949502040608010004080120160200240280320360400440480520560600DiskFailureRate(%)RScountA-2RSCharacterization(1)18Copyright2015EMCCorporation.
Allrightsreserved.
LargerRScount,fastertofail10%25%median75%90%RSCountTimeMargin(Days)DiskFailureTimeGivenDifferentRSCountRSCharacterization(2)19Copyright2015EMCCorporation.
Allrightsreserved.
RScountindicatesthedegreeofdiskreliabilitydeteriorationUsetheRScounttopredictimpendingdiskfailureinadvancePLATE:SingleDiskProactiveProtection20Copyright2015EMCCorporation.
Allrightsreserved.
70.
166.
66461.
859.
952.
14742.
63936.
94.
52.
82.
11.
71.
40.
80.
70.
40.
30.
27010203040506070809010020406080100200300400500600failurespredictedfalsepositivePercentage(%)BoththepredictedfailureandfalsepositiveratesdecreaseasthethresholdincreasesSimulationResult:FailuresCapturedRateGivenDifferentRSThresholdRSthreshold21Copyright2015EMCCorporation.
Allrightsreserved.
551515801070020406080100WithoutProactiveProtectionWithProactiveProtectionHardwareFailuresOthersTripleFailuresEliminatedTripleFailuresSingleproactiveprotectionreducesabout70%ofRAIDfailures,equivalentto88%ofthetriple-diskfailuresPLATEDeploymentResult:CausesofRecoveryIncidentsPercentage(%)22Copyright2015EMCCorporation.
Allrightsreserved.
10%remainingtriplefailuresPLATEmissesRAIDfailurescausedbymultiplelessreliabledrives,whoseRScountshaven'texceedthethresholdTriagePrioritizediskgroupswithhighestriskMotivationofARMOR:TheRAIDGroupProactiveProtection23Copyright2015EMCCorporation.
Allrightsreserved.
1-11-21-31-42-12-22-32-43-13-23-33-44-14-24-34-4XXXXThreatofFailureImminentFailureGoodDiskHealthyDG1ImminentFailureofDG2ProtectedDG3PossibleFailureofDG4Singlediskprotection:Replace2-3,2-4,3-4(PLATE)Can'tidentifyDG4northedifferencebetweenDG2andDG3Groupprotection:ReplaceDG4orincreaseredundancy(ARMOR)ProtectDG4andrecognizethedifferencebetweenDG2andDG3DiskGroupProtectionExample24Copyright2015EMCCorporation.
Allrightsreserved.
CalculatethesinglediskfailureprobabilityConditionalprobabilitythroughBayesTheoremCalculatetheprobabilityofavulnerableRAIDCombinationofthosesinglediskprobabilitiesthroughjointprobabilityARMORMethodology25Copyright2015EMCCorporation.
Allrightsreserved.
ThediscriminationshowsARMORiseffectivetorecognizeendangeredDGsInpractice,itidentifiesmostDGfailuresthatarenotpredictedbyPLATEProbabilityDecilesdistributionEvaluation0.
250.
330.
390.
440.
460.
50.
630.
730.
930.
150.
20.
230.
250.
270.
280.
30.
310.
3200.
20.
40.
60.
81123456789GroupswithmorethanonefailureGroupswithoutfailure26Copyright2015EMCCorporation.
Allrightsreserved.
GooglereportsSMARTmetricssuchasreallocatedsectorstronglysuggestanimpendingfailure,buttheyalsodeterminethathalfofthefaileddisksshownosucherrors[Pinheiro'07]DifferentworkloadandRAIDrewriteDiskfailurepredictionAveragemaximumlatency[Goldszmidt'12]SMARTfailureprediction[Murray'05,Hughes'02]RelatedWork27Copyright2015EMCCorporation.
Allrightsreserved.
Weanalyzed1millionSATAdrivesObservefailuremodesdegradingRAIDreliabilityRevealRScountreflectsthediskreliabilitydeteriorationDiskfailureispredictableWebuiltRAIDSHIELD,anactivedefensemechanismPLATE:singlediskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroups–HopetodeployinfutureIsaddingextraredundancyanefficientsolutionUseasmuchredundancyasneededtoensureavailabilityProactivereplacementshoulddecreasethelevelneededSummary28Copyright2015EMCCorporation.
Allrightsreserved.
RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresQuestionsAcknowledgementAndreaArpaci-DusseauandRemziArpaci-DusseauDataDomainengineerteam,membersofADandCTOoffice,StephenManley29Copyright2015EMCCorporation.
Allrightsreserved.
CalculatethesinglediskfailureprobabilityCalculatetheprobabilityofavulnerableRAID
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继阿里云服务商推出轻量服务器后，腾讯云这两年对于轻量服务器的推广力度还是比较大的。实际上对于我们大部分网友用户来说，轻量服务器对于我们网站和一般的业务来说是绝对够用的。反而有些时候轻量服务器的带宽比CVM云服务器够大，配置也够好，更有是价格也便宜，所以对于初期的网站业务来说轻量服务器是够用的。这几天UCLOUD优刻得香港服务器稳定性不佳，于是有网友也在考虑搬迁到腾讯云服务器商家，对于轻量服务器官方...
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