Lenovo ThinkServer TD340 - Configuring RAID; About RAID

ConfiguringRAID
ThistopicprovidesinformationaboutRAIDandtheutilityprogramsthatareavailableforyoutoconfigure
RAID.
Thistopiccontainsthefollowingitems:
•“AboutRAID”onpage72
•“ConfiguringRAIDusingtheThinkServerEasyStartupprogram”onpage73
•“ConfiguringtheThinkServerRAID100orRAID300”onpage74
•“ConfiguringtheadvancedSATA/SAShardwareRAID”onpage79
AboutRAID
RAID,anacronymforRedundantArrayofIndependentDisks,isatechnologythatprovidesincreased
storagefunctionsandreliabilitythroughredundancy.Thisisachievedbycombiningmultipleharddiskdrives
intoalogicalunit,wheredataisdistributedacrossthedrivesinoneofseveralwayscalledRAIDlevels.
WhenagroupofindependentphysicalharddiskdrivesaresetuptouseRAIDtechnology,theyareina
RAIDarray.Thisarraydistributesdataacrossmultipleharddiskdrives,butthearrayappearstothehost
serverasonesinglestorageunit.CreatingandusingRAIDarraysprovideshighperformance,suchasthe
expeditedI/Operformance,becauseseveraldrivescanbeaccessedsimultaneously.
RAIDdrivegroupsalsoimprovedatastoragereliabilityandfaulttolerancecomparedwithsingle-drive
storagesystems.Datalossresultingfromadrivefailurecanbepreventedbyreconstructingmissingdata
fromtheremainingdrives.
ThefollowinglistdescribessomeofthemostcommonlyusedRAIDlevels:
•RAID0:block-levelstripingwithoutparityormirroring
SimplestripesetsarenormallyreferredtoasRAID0.RAID0usesstripingtoprovidehighdata
throughput,especiallyforlargefilesinanenvironmentthatdoesnotrequirefaulttolerance.RAID0hasno
redundancyanditprovidesimprovedperformanceandadditionalstoragewithoutfaulttolerance.Any
drivefailuredestroysthearrayandthelikelihoodoffailureincreaseswithmoredrivesinthearray.RAID
0doesnotimplementerrorchecking,soanyerrorisuncorrectable.Moredrivesinthearraymeans
higherbandwidth,butgreaterriskofdataloss.
RAID0requiresaminimumnumberoftwoharddiskdrives.
•RAID1:mirroringwithoutparityorstriping
RAID1usesmirroringsothatdatawrittentoonedriveissimultaneouslywrittentoanotherdrive.Thisis
goodforsmalldatabasesorotherapplicationsthatrequiresmallcapacitybutcompletedataredundancy.
RAID1providesfaulttolerancefromdiskerrorsorfailuresandcontinuestooperateaslongasatleast
onedriveinthemirroredsetisfunctioning.Withappropriateoperatingsystemsupport,therecanbe
increasedreadperformanceandonlyaminimalwriteperformancereduction.
RAID1requiresaminimumnumberoftwoharddiskdrives.
72ThinkServerTD340UserGuideandHardwareMaintenanceManual