Specifications

Storage Subsystem Guide 31
Creating System Drives
IntheRAIDLevelpage,selectaRAIDlevel,thenclickNext.
ForinformationaboutRAIDlevels1,5and6,refertothefollowingtable.
RAID
Level
SystemDrive
Size
DescriptionandFailover Advantages/Disadvantages
12to32disks,
upto2TBor,
>2TBwiththe
proper
controller
firmwareand
disktype
(contactSGI
Global
Servicesfor
more
information)
Providesmirroringand
duplexing.
Ifaphysicaldiskfailsandahot
sparediskisavailable,the
controllerautomatically
inserts
thespareandbuildsontoitthe
contentsofthefaileddisk.
Datawrittentoonediskis
duplicatedtoasecondformaximum
dataprotection,butwithonly50%
usablecapacity.
53to16FCor
SASdisks,>2
TB,or3to16
SATAdisks
upto2TB

Providesacombinationof
stripingandparitychecking.
Ifaphysicaldiskfailsandahot
sparediskisavailable,the
controllerautomaticallyinserts
thespareandbuildsontoitthe
contentsofthefaileddisk,from
dataandparityinformationon
theremainingdisks.Formany
applications,RAID5
offersa
goodcompromisebetween
capacity,reliability,andspeed.
Paritycheckingprovides
redundancywithouttheoverheadof
havingtodoublethediskcapacity.