RAID 6 plus a hotspare: overkill or just being extra cautious?

Once you get to 2TB or larger drives, you definitely should go with RAID 6, because of the amount of time it can take to recover a drive. Once you're exceeded 9 ... Foundtheinternet!17RAID6plusahotspare:overkillorjustbeingextracautious? Close17Postedby10yearsagoRAID6plusahotspare:overkillorjustbeingextracautious? Iamsettingupanewserver.IamsettingupthediskarrayasRAID6plusahotspare.IknowthatRAID6canloseuptotwodiskswithoutlossofdata.Iwouldratherknowthatifadiskfailsthatthearraywillstartbuildingareplacementwiththehotsparerightaway.Or...isRAID6goodenoughthatthereisnoneedofreservingahotspareanymore?85commentssharesavehidereport80%UpvotedLoginorsignuptoleaveacommentLogInSignUpSortby:best level1·10yr.agoCanneverbetoocareful.26ReplyShareReportSaveFollowlevel1·10yr.agoPrincipleSRE24yrs/13jobsRAID!=backups,nomatterhowyouallocatethedisks.I'dleavewellenoughalonewithRAID6andstartworkonbackupanddisasterrecoveryprocesses.14ReplyShareReportSaveFollowlevel2·10yr.agoTheOPneversaidthatbut,whilewe'reonthesubject:REPLICATION!=backups!7ReplyShareReportSaveFollowContinuethisthread level2Commentdeletedbyuser·10yr.agoContinuethisthread level2·10yr.agoThisisoneofthetimestheOPdidn'tsaythat2ReplyShareReportSaveFollowContinuethisthread level1·10yr.agoWejustlostaSANthatwasconfiguredRAID50withhotspares.Welostadrive,then15hourslaterwiththerebuildat92%,welostaseconddrivefromthesameRAID5.ThiswastheSANthathousedmostofourvmwareenvironment,solosingthearraymeantdowntimeon~75%ofthedatacenter.Obviouslyyouhavetoevaluateyourownsituation,butIwoulddefinitelynotconsiderRAID6plushotsparetobeoverkill.5ReplyShareReportSaveFollowlevel2Op·10yr.agoWhew.Thankyouforconfirmingmyparanoia.3ReplyShareReportSaveFollowlevel2·10yr.agoWhattypeofarray?1ReplyShareReportSaveFollowContinuethisthread level1·10yr.agoJackofAllTradesIruna6x2TBRAID6arrayforpersonalusewitha7th2TBdriveasahotspare.GivesmealittlepeaceofmindincaseIloseadrivewhenI'mnoton-site.3ReplyShareReportSaveFollowlevel1·10yr.agoHowmanydisksinthearray?3ReplyShareReportSaveFollowlevel2Op·10yr.agoSix.1ReplyShareReportSaveFollowContinuethisthread level1·10yr.agoStorageAdminWith7200RPMdrivesover2TBinanysortofquantity,it'snearlyanecessity.3ReplyShareReportSaveFollowlevel2Op·10yr.ago15000RPMdrives,600GBeach,6MbpsSAS.IwasgoingforspeedforaSQLserver.3ReplyShareReportSaveFollowContinuethisthread level1·10yr.agoItdependsonthesizeandnumberofdrives.Ifit'salargearray,thentheanswerisdefinitelyyes.Onceyougetto2TBorlargerdrives,youdefinitelyshouldgowithRAID6,becauseoftheamountoftimeitcantaketorecoveradrive.Onceyou'reexceeded9orsodrives,youshouldstartusingRAID6andahotspare,sincethechanceofadrivefailingcanberelativelyhigh.Ononeserver,Ihave12x2TBdrives,soRAID6withahotsparewastheonlywayIwouldhaveconsideredsettingitup.Youmaynotwanttolosethespaceofonedrive,butthathotsparecanreallysaveyouonalargearray.3ReplyShareReportSaveFollowlevel1·10yr.agoLinuxHPCgraybeardYourquestionleavesoutthemostimportantthing:whatdatawillthisarrayhold?Howimportantisit?Also,whatarethecharacteristicsofdegradedraidsetsinyourraidcontrollers?Istheperformancebadenoughthatitwillbeproblematictoyourusers?What'stherebuildtime?Willaddingorsubtractingthelastdiskchangethestripesizetoasufficientdegreetocauseyourapplicationproblems?Anecdotaldatapoint:atnotimesincebefore2007haveIbeenresponsibleforlessthan800x10-diskRAID6sets(andattimesmanymore),withnospareswhatsoever,andhavesufferedthelossofagrandtotalofzeroraidsets.Weuseratherfancyraidcontrollers,socrappyonboardcardsmaychangethisconsiderably.Also:atacertainpoint,it'saboutwhatmakesyousleepbetter.Ifyou'llsleepbetterwiththespareanditwon'tmaketheperformancesignificantlyworse,youshoulddoit.3ReplyShareReportSaveFollowlevel2·10yr.agoLinuxadmin(HPC)Yeah,wedon'trunhotspares.Butwedoruncrazycount'sofraid61ReplyShareReportSaveFollowlevel1·10yr.agoJackofAllTradesIwouldsaythatitdepends.Ifallthedrivesarefromthesameproductionseries,thentheyareproducedwithinthesametimeperiod.Whichmeansthatwhenonestartsfailing,theotherswillmostlikelyfollowprettywithinashorttimespan.Thisdoesnotneedtobecausedbyproduction,butsimplybadtransportation+++.Note:RebuildingaRAIDwillalsocauseelevatedstressontheotherdrives.Ifthedrivesarefromseparateproductions,thisdangershouldnotbeanythingtoworryabout,andaregularRAID6shouldsuffice.FYI:IhavehadthepleasuretohaveaRAID5lostduetodrivetwofromaseriesdyingwithin24hoursofthefirstdrive,nowidoRAID5;)Thedrivesarefromtwoseries,soisticktonohotspares.2ReplyShareReportSaveFollowlevel1·10yr.agoRAID6+Coldspare(areplacementdrivesomewhereyoucangetitwithin10minutes)willbemorethanenough.Statistically,anyway.2ReplyShareReportSaveFollowlevel2·10yr.agoThisassumesthedatacenter/colocationismanned,andpeoplewillnotice&beabletoreplaceadrivewithin10minutesofafailure.(Thisiswhyhotsparesaresonice)1ReplyShareReportSaveFollowToppostsjune7th2012,Toppostsofjune,2012,Topposts2012,helpRedditcoinsRedditpremiumaboutcareerspressadvertiseblogTermsContentpolicyPrivacypolicyModpolicyRedditInc©2022.AllrightsreservedBacktoTop Advertisement