Raid faq

FAQ | RAID

RAID 1–Createsasinglevolumeoutoftwodrives.ThedrivesaretypicallyononecontrollerunlessControllerSpanning

issupported.Thedataonthetwodrivesaremirrorimagesofeachother.Thesizeofthemirrorislimitedbythesmallest

driveusedintheRAID1conguration.Thiscongurationprovidesdataredundancyprotectionagainstasingledrive

failure,doesnotuseparity,anddoesnotimproveperformance.Ifadrivefails,thedrivecanbereplacedbyadriveofthe

samecapacityorlargertorebuildtheRAIDarray.Ifonedrivefails,dataisnotlost.ThemainadvantageofRAID1is

data integrity.

RAID 5–Createsasinglevolumefromthreeormorephysicaldrives,typicallyononecontroller,althoughitispossible

tosupportmultiplecontrollersifControllerSpanningissupported.RAID5usesstripingwithparitydataindistributed

blocksacrossallmemberdisks.ARAID5volumeistolerantofasinglediskfailure.RAID5hasperformanceattributes

similartoaRAID0congurationandthereliabilityofRAID1,however,paritycalculationscanreducetheperformance

relativetoaRAID0conguration.RAID5addsdistributedparitytoblock-levelstriping.So,RAID5hasgoodread

performanceaswellasexcellentredundancy.Dataintegritycanbemaintainedafterasingledrivefailure.RAID5also

supportshotsparecapabilityoncertaincontrollers(seebelow).ThemainadvantageofRAID5isspeed/performance

and data integrity.

Logical disk

RAID 1 disk array

Logical disk

RAID 5 disk array

Data stripe

Parity