Data Protection RAID.ppt

dataprotection raid module1 3 dataprotection raid 2 moduleobjectives aftercompletingthismodule youwillbeableto describewhatisraidandtheneedsitaddressesdescribetheconceptsuponwhichraidisbuiltdefineandcompareraidlevelsrecommendtheuseofthecommonraidlevelsbasedonperformanceandavailabilityconsiderationsexplainfactorsimpactingdiskdriveperformance dataprotection raid 3 whyraid performancelimitationofdiskdriveanindividualdrivehasacertainlifeexpectancymeasuredinmtbfexampleifthemtbfofadriveis750 000hours andthereare100drivesinthearray thenthemtbfofthearraybecomes750 000 100 or7 500hoursraidwasintroducedtomitigatethisproblemraidprovides increasecapacityhigheravailabilityincreasedperformance redundantarrayofindependentdisks redundantarrayofinexpensivedisks dataprotection raid 4 raidarraycomponents raidcontroller harddisks logicalarray physicalarray raidarray host dataprotection raid 5 raidimplementations hardware usuallyaspecializeddiskcontrollercard controlsalldrivesattachedtoitarray s appeartohostoperatingsystemasaregulardiskdriveprovidedwithadministrativesoftwaresoftwarerunsaspartoftheoperatingsystemperformanceisdependentoncpuworkloaddoesnotsupportallraidlevels dataprotection raid 6 raidcontrollercard dataprotection raid 7 raidlevels 0stripedarraywithnofaulttolerance1diskmirroringnestedraid i e 1 0 0 1 etc 3parallelaccessarraywithdedicatedparitydisk4stripedarraywithindependentdisksandadedicatedparitydisk5stripedarraywithindependentdisksanddistributedparity6stripedarraywithindependentdisksanddualdistributedparity dataprotection raid 8 dataorganization striping stripe1 stripe2 strips strip1 strip2 strip3 dataprotection raid 9 raid0 stripedarraywithnofaulttolerance 1 9 5 2 10 6 3 11 7 0 host dataprotection raid 10 raid1 diskmirroring host raidcontroller dataprotection raid 11 nestedraid 0 1 stripingandmirroring host dataprotection raid 12 nestedraid 0 1 stripingandmirroring host dataprotection raid 13 host nestedraid 1 0 mirroringandstriping dataprotection raid 14 host nestedraid 1 0 mirroringandstriping dataprotection raid 15 raidredundancy parity paritydisk 1 9 5 3 11 7 0 0123 4567 4 6 1 7 18 host paritycalculation4 6 1 7 18 4 6 7 18 18 4 6 7 1 dataprotection raid 16 host raid3 parallelaccessarraywithdedicatedparitydisk bit interleavedparity dataprotection raid 17 raid4 stripedarraywithindependentdisksandadedicatedparitydisk block interleavedparity host dataprotection raid 18 host raid5 stripedarraywithindependentdisksanddistributedparity dataprotection raid 19 raid6 dualparityraid twodiskfailuresinaraidsetleadstodataunavailabilityanddatalossinsingle parityschemes suchasraid 3 4 and5increasingnumberofdrivesinanarrayandincreasingdrivecapacityleadstoahigherprobabilityoftwodisksfailinginaraidsetraid 6protectsagainsttwodiskfailuresbymaintainingtwoparitieshorizontalparitywhichisthesameasraid 5paritydiagonalparityiscalculatedbytakingdiagonalsetsofdatablocksfromtheraidsetmemberseven odd andreed solomonaretwocommonlyusedalgorithmsforcalculatingparityinraid 6 dataprotection raid 20 raid6 p q dataprotection raid 21 raid6 dp diagonalparity dataprotection raid 22 raidcomparison dataprotection raid 23 small lessthanelementsize writeonraid3 5ep e1 e2 e3 e4 xoroperations ifparityisvalid then epnew epold e4old e4new xoroperations 2diskreadsand2diskwritesparityvsmirroringreading calculatingandwritingparitysegmentintroducespenaltytoeverywriteoperationparityraidpenaltymanifestsduetoslowercacheflushesincreasedloadinwritescancausecontentionandcancauseslowerreadresponsetimes epnew raidcontroller 2xor epnew epold e4old e4new e4old epold e4new raidimpactsonperformance p0 d1 d2 d3 d4 dataprotection raid 24 raidpenaltyexercise totaliopsatpeakworkloadis1200read writeratio2 1calculateiopsrequirementatpeakactivityforraid1 0raid5 dataprotection raid 25 solution totaliops 1200read writratio2 1forraid1 0 1200 x2 3 1200 x 1 3 x2 800 800 1600iopsforraid5 1200 x2 3 1200 x 1 3 x4 800 1600 2400iops dataprotection raid 26 hotspares dataprotection raid 27 modulesummary keypointscoveredinthismodule whatraidisandtheneedsitaddressestheconceptsuponwhichraidisbuiltsomecommonlyimplementedraidlevels dataprotection raid 28 chec