Lenovo ThinkServer TS440 - Configuring RAID

•ViewinformationaboutallservermodelssupportedbytheThinkServerEasyStartupprogramand
informationaboutthedevicedriversforeachservermodel,includingthedriverversionsanddriver
locationsintherootdirectoryoftheThinkServerEasyStartupDVD.
Note:Themostup-to-datedevicedriversforvariousservermodelsarealwaysavailablefordownloadon
theLenovoSupportWebsiteat:
http://www.lenovo.com/drivers
ConguringRAID
ThistopicprovidesinformationaboutRAIDandtheutilityprogramsthatareavailableforyoutocongure
RAID.
Thistopiccontainsthefollowingitems:
•“AboutRAID”onpage55
•“RAIDforyourserver”onpage56
•“ConguringthesystemBIOStoenableonboardSATARAIDfunctionality”onpage57
•“ConguringtheadvancedSATAorSAShardwareRAID”onpage58
AboutRAID
RAID,anacronymforRedundantArrayofIndependentDisks,isatechnologythatprovidesincreased
storagefunctionsandreliabilitythroughredundancy.Thisisachievedbycombiningmultipleharddiskdrives
intoalogicalunit,wheredataisdistributedacrossthedrivesinoneofseveralwayscalledRAIDlevels.
WhenagroupofindependentphysicalharddiskdrivesaresetuptouseRAIDtechnology,theyareina
RAIDarray.Thisarraydistributesdataacrossmultipleharddiskdrives,butthearrayappearstothehost
serverasonesinglestorageunit.CreatingandusingRAIDarraysprovideshighperformance,suchasthe
expeditedI/Operformance,becauseseveraldrivescanbeaccessedsimultaneously.
RAIDdrivegroupsalsoimprovedatastoragereliabilityandfaulttolerancecomparedtosingle-drivestorage
systems.Datalossresultingfromadrivefailurecanbepreventedbyreconstructingmissingdatafromthe
remainingdrives.
ThefollowinglistdescribessomeofthemostcommonlyusedRAIDlevels:
•RAID0:block-levelstripingwithoutparityormirroring
SimplestripesetsarenormallyreferredtoasRAID0.RAID0usesstripingtoprovidehighdata
throughput,especiallyforlargelesinanenvironmentthatdoesnotrequirefaulttolerance.RAID0hasno
redundancyanditprovidesimprovedperformanceandadditionalstoragewithoutfaulttolerance.Any
drivefailuredestroysthearrayandthelikelihoodoffailureincreaseswithmoredrivesinthearray.RAID
0doesnotimplementerrorchecking,soanyerrorisuncorrectable.Moredrivesinthearraymeans
higherbandwidth,butgreaterriskofdataloss.
RAID0requiresaminimumnumberoftwoharddiskdrives.
•RAID1:mirroringwithoutparityorstriping
RAID1usesmirroringsothatdatawrittentoonedriveissimultaneouslywrittentoanotherdrive.Thisis
goodforsmalldatabasesorotherapplicationsthatrequiresmallcapacitybutcompletedataredundancy.
RAID1providesfaulttolerancefromdiskerrorsorfailuresandcontinuestooperateaslongasatleast
onedriveinthemirroredsetisfunctioning.Withappropriateoperatingsystemsupport,therecanbe
increasedreadperformanceandonlyaminimalwriteperformancereduction.
RAID1requiresaminimumnumberoftwoharddiskdrives.
Chapter5.Conguringtheserver55