Lenovo ThinkServer RS160 - Page 52

ConfiguringRAID
ThistopicprovidesinformationaboutRAIDandtheutilityprogramsthatareavailableforyoutoconfigure
RAID.
Thistopiccontainsthefollowingitems:
•“AboutRAID”onpage38
•“RAIDforyourserver”onpage39
•“ConfiguringonboardSATAsoftwareRAID”onpage40
•“ConfiguringadvancedSATAorSAShardwareRAID”onpage42
AboutRAID
RAID,anacronymforRedundantArrayofIndependentDisks,isatechnologythatprovidesincreased
storagefunctionsandreliabilitythroughredundancy.ThisisachievedbycombiningmultipleHDDsintoa
logicalunit,wheredataisdistributedacrossthedrivesinoneofseveralwayscalledRAIDlevels.
WhenagroupofindependentphysicalHDDsaresetuptouseRAIDtechnology,theyareinaRAIDarray.
ThisarraydistributesdataacrossmultipleHDDs,butthearrayappearstothehostserverasonesingle
storageunit.CreatingandusingRAIDarraysprovideshighperformance,suchastheexpeditedI/O
performance,becauseseveraldrivescanbeaccessedsimultaneously.
RAIDdrivegroupsalsoimprovedatastoragereliabilityandfaulttolerancecomparedwithsingle-drive
storagesystems.Datalossresultingfromadrivefailurecanbepreventedbyreconstructingmissingdata
fromtheremainingdrives.
ThefollowinglistdescribessomeofthemostcommonlyusedRAIDlevels:
•RAID0:block-levelstripingwithoutparityormirroring
SimplestripesetsarenormallyreferredtoasRAID0.RAID0usesstripingtoprovidehighdata
throughput,especiallyforlargefilesinanenvironmentthatdoesnotrequirefaulttolerance.RAID0hasno
redundancyanditprovidesimprovedperformanceandadditionalstoragewithoutfaulttolerance.Any
drivefailuredestroysthearrayandthelikelihoodoffailureincreaseswithmoredrivesinthearray.RAID
0doesnotimplementerrorchecking,soanyerrorisuncorrectable.Moredrivesinthearraymeans
higherbandwidth,butgreaterriskofdataloss.
RAID0requiresaminimumnumberofoneHDD.
•RAID1:mirroringwithoutparityorstriping
RAID1usesmirroringsothatdatawrittentoonedriveissimultaneouslywrittentoanotherdrive.Thisis
goodforsmalldatabasesorotherapplicationsthatrequiresmallcapacitybutcompletedataredundancy.
RAID1providesfaulttolerancefromdiskerrorsorfailuresandcontinuestooperateaslongasatleast
onedriveinthemirroredsetisfunctioning.Withappropriateoperatingsystemsupport,therecanbe
increasedreadperformanceandonlyaminimalwriteperformancereduction.
RAID1requiresaminimumnumberoftwoHDDs.
38ThinkServerRS160UserGuideandHardwareMaintenanceManual