1Copyright2015EMCCorporation.
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RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresPresenter:AoMaAjointworkwithFredDouglis,GuanlinLu,DarrenSawyerSurendarChandra,WindsorHsu2Copyright2015EMCCorporation.
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DiskfailuresarecommonplaceWhole-diskfailurePartialfailureRAIDiswidelydeployedProtectdataagainstfailureswithredundancyPervasiveRAIDProtection3Copyright2015EMCCorporation.
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StoragesystemisevolvingEscalateduseoflessreliabledrivescausesmorewhole-diskfailuresIncreasingdiskcapacityresultsinmoresectorerrorsSolutionAddextraredundancy(RAID5,RAID6,…)–EnsuredatareliabilityatthecostofstorageefficiencyRAIDOverviewIsaddingextraredundancyanefficientsolution4Copyright2015EMCCorporation.
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Analyzed1millionSATAdisksandrevealedFailuremodesdegradingRAIDreliabilityReallocatedsectorsreflectdiskreliabilitydeteriorationDiskfailureispredictableBuiltRAIDSHIELD,anactivedefensemechanismReconstructfailingdiskbeforeit'stoolate!
PLATE:single-diskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroupsWhatWeDid5Copyright2015EMCCorporation.
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BackgroundDiskfailureanalysisRAIDSHIELD:IdentifyfailureindicatorReallocatedSector(RS)characterizationSinglediskproactiveprotectionDiskgroupproactiveprotection5Outline6Copyright2015EMCCorporation.
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Diskfailuredoesnotfollowafail-stopmodelTheproductionsystemsstudieddefinefailureasConnectionislostAnoperationexceedsthetimeoutthresholdWritefailsWhole-diskFailureDefinition7Copyright2015EMCCorporation.
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EachdiskdrivemodelisdenotedasRelativesizeswithinafamilyareorderedbythecapacitynumber–E.
g.
A-2islargerthanA-1DiskModelPopulation(Thousands)FirstDeploymentLogLength(Months)A-13406/200860A-216511/200860B-110006/200848C-19310/201036C-225312/201036D-138409/201121DiskDataCollection8Copyright2015EMCCorporation.
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WhatDoRealDiskFailuresLookLike9Copyright2015EMCCorporation.
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0001424462031010203040500-612-1824-3036-4248-54A-2MonthDistributionofLifetimeofFailedDrives001241534291130102030400-612-1824-3036-4248-54A-1MonthAlargefractionoffaileddrivesarefoundatasimilaragePercentage(%)Percentage(%)10Copyright2015EMCCorporation.
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ThenumberofaffecteddiskskeepgrowingAbout10%ofdisksgetsectorerrorsatthe3rdyearSectorerrornumbersincreasescontinuouslyAverageerrorcountincreases25%to300%yearoveryearIncreasingFrequencyofSectorErrors11Copyright2015EMCCorporation.
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DrivefailingatasimilarageFailurerateisnotconstantAhighriskofmultiplesimultaneousfailuresIncreasingfrequencyofsectorerrorsExacerbateriskofreconstructionfailuresPassiveRedundancyisInefficientEnsuringreliabilityintheworstcaserequiresaddingconsiderableextraredundancy,makingitunattractivefromacostperspective12Copyright2015EMCCorporation.
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MotivationEnsuredatasafetywithminimalredundancyProactivelyrecognizeimpendingfailuresandmigratevulnerabledatainadvanceMethodologyIdentifyindicatorofimpendingfailureIndicatorcharacterizationProactiveprotectionRAIDSHIELD,TheProactiveProtection13Copyright2015EMCCorporation.
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PotentialindicatorsVariousdiskerrorsCriteriaofagoodindicatorIthappensmuchmorefrequentlyonfaileddisksratherthanworkingdisksApproachQuantifythediscriminationbetweenerrorvalueonfaileddisksandworkingones–DecilescomparisonisusedIdentifyFailureIndicator14Copyright2015EMCCorporation.
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FaileddiskshavemoremediaerrorsthanworkingonesThediscriminationisnotsignificantenoughMediaErrorComparison2359152232478611123471330020406080100123456789faileddiskworkingdiskDecilesA-2MediaErrorCount15Copyright2015EMCCorporation.
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2238718732752281212422025000001262905001000150020002500123456789faileddiskworkingdiskA-2DecilesReallocatedSectorCountA-2DecilesRSisstronglycorrelatedwithdiskfailuresReallocatedSector(RS)Comparison16Copyright2015EMCCorporation.
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MostfaileddrivestendtohavealargernumberofRSthanworkingonesRSisstronglycorrelatedwithwhole-diskfailures,followedbymediaerrors,pendingsectorerrorsanduncorrectablesectorerrorsCorrelationBetweenSectorErrorsAndWhole-diskFailureRSisastrongindicatorofimpendingdiskfailure17Copyright2015EMCCorporation.
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LargerRScountimplieshigherfailurerateintwo-monthwindowDiskFailureRateGivenDifferentRSCount1.
767758083858689909091929393949502040608010004080120160200240280320360400440480520560600DiskFailureRate(%)RScountA-2RSCharacterization(1)18Copyright2015EMCCorporation.
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LargerRScount,fastertofail10%25%median75%90%RSCountTimeMargin(Days)DiskFailureTimeGivenDifferentRSCountRSCharacterization(2)19Copyright2015EMCCorporation.
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RScountindicatesthedegreeofdiskreliabilitydeteriorationUsetheRScounttopredictimpendingdiskfailureinadvancePLATE:SingleDiskProactiveProtection20Copyright2015EMCCorporation.
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70.
166.
66461.
859.
952.
14742.
63936.
94.
52.
82.
11.
71.
40.
80.
70.
40.
30.
27010203040506070809010020406080100200300400500600failurespredictedfalsepositivePercentage(%)BoththepredictedfailureandfalsepositiveratesdecreaseasthethresholdincreasesSimulationResult:FailuresCapturedRateGivenDifferentRSThresholdRSthreshold21Copyright2015EMCCorporation.
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551515801070020406080100WithoutProactiveProtectionWithProactiveProtectionHardwareFailuresOthersTripleFailuresEliminatedTripleFailuresSingleproactiveprotectionreducesabout70%ofRAIDfailures,equivalentto88%ofthetriple-diskfailuresPLATEDeploymentResult:CausesofRecoveryIncidentsPercentage(%)22Copyright2015EMCCorporation.
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10%remainingtriplefailuresPLATEmissesRAIDfailurescausedbymultiplelessreliabledrives,whoseRScountshaven'texceedthethresholdTriagePrioritizediskgroupswithhighestriskMotivationofARMOR:TheRAIDGroupProactiveProtection23Copyright2015EMCCorporation.
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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.
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CalculatethesinglediskfailureprobabilityConditionalprobabilitythroughBayesTheoremCalculatetheprobabilityofavulnerableRAIDCombinationofthosesinglediskprobabilitiesthroughjointprobabilityARMORMethodology25Copyright2015EMCCorporation.
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ThediscriminationshowsARMORiseffectivetorecognizeendangeredDGsInpractice,itidentifiesmostDGfailuresthatarenotpredictedbyPLATEProbabilityDecilesdistributionEvaluation0.
250.
330.
390.
440.
460.
50.
630.
730.
930.
150.
20.
230.
250.
270.
280.
30.
310.
3200.
20.
40.
60.
81123456789GroupswithmorethanonefailureGroupswithoutfailure26Copyright2015EMCCorporation.
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GooglereportsSMARTmetricssuchasreallocatedsectorstronglysuggestanimpendingfailure,buttheyalsodeterminethathalfofthefaileddisksshownosucherrors[Pinheiro'07]DifferentworkloadandRAIDrewriteDiskfailurepredictionAveragemaximumlatency[Goldszmidt'12]SMARTfailureprediction[Murray'05,Hughes'02]RelatedWork27Copyright2015EMCCorporation.
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Weanalyzed1millionSATAdrivesObservefailuremodesdegradingRAIDreliabilityRevealRScountreflectsthediskreliabilitydeteriorationDiskfailureispredictableWebuiltRAIDSHIELD,anactivedefensemechanismPLATE:singlediskproactiveprotection–Deploymenteliminates70%ofRAIDfailuresARMOR:diskgroupproactiveprotection–RecognizevulnerableRAIDgroups–HopetodeployinfutureIsaddingextraredundancyanefficientsolutionUseasmuchredundancyasneededtoensureavailabilityProactivereplacementshoulddecreasethelevelneededSummary28Copyright2015EMCCorporation.
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RAIDShield:Characterizing,Monitoring,andProactivelyProtectingAgainstDiskFailuresQuestionsAcknowledgementAndreaArpaci-DusseauandRemziArpaci-DusseauDataDomainengineerteam,membersofADandCTOoffice,StephenManley29Copyright2015EMCCorporation.
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CalculatethesinglediskfailureprobabilityCalculatetheprobabilityofavulnerableRAID
这次RackNerd商家提供的美国大硬盘独立服务器,数据中心位于洛杉矶multacom,可选Windows、Linux镜像系统,默认内存是64GB,也可升级至128GB内存,而且硬盘采用的是256G SSD系统盘+10个16TSAS数据盘,端口提供的是1Gbps带宽,每月提供200TB,且包含5个IPv4,如果有需要更多IP,也可以升级增加。CPU核心内存硬盘流量带宽价格选择2XE5-2640V2...
2022年春节假期陆续结束,根据惯例在春节之后各大云服务商会继续开始一年的促销活动。今年二月中旬会开启新春采购季的活动,我们已经看到腾讯云商家在春节期间已经有预告活动。当时已经看到有抢先优惠促销活动,目前我们企业和个人可以领取腾讯云代金券满减活动,以及企业用户可以领取域名优惠低至.COM域名1元。 直达链接 - 腾讯云新春采购活动抢先看活动时间:2022年1月20日至2022年2月15日我们可以在...
最近发现一个比较怪异的事情,在访问和登录大部分国外主机商和域名商的时候都需要二次验证。常见的就是需要我们勾选判断是不是真人。以及比如在刚才要访问Namecheap检查前几天送给网友域名的账户域名是否转出的,再次登录网站的时候又需要人机验证。这里有看到"Attention Required"的提示。我们只能手工选择按钮,然后根据验证码进行选择合适的标记。这次我要选择的是船的标识,每次需要选择三个,一...
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