Raid FAQ

8
FAQ | RAID
What is the dierence between hardware RAID & software RAID?
HardwareRAIDisimplementedusingdedicatedRAIDhardwareassociatedwithaRAIDstoragecontrollerthatthedisk
drivesareconnectedtointhesystem.Typically,asingledatatransactionissenttotheRAIDstoragecontroller.Then,the
storagecontrollerisresponsibleformanagingandsendingdatatotheindividualdrivesintheRAID.RAIDprovidesbetter
performancebecauseofthishardwareandistypicallymorereliablethansoftwareRAID.InsoftwareRAID,thedrive
sendsmultipletransactionstothestoragecontrollerandtoeachindividualdriveintheRAID.HardwareRAIDhasmore
congurationoptionsbutcanbeamoreexpensivesolutionbecauseoftheaddedhardwarecost.
SoftwareRAIDcanbeimplementedbytheoperatingsystem(OS)orbyathirdpartysoftware/driverrunningonthesystem.
SoftwareRAIDaddsmorelatencyinthesoftwarestackbutistypicallyavailableatalowerpricepoint.Theperformanceof
softwareRAIDisdependentonsystemloadandthebandwidthavailabletothestoragecontrollerandeachdrive.
Controller Usage Specics
What should I know about the built-in controller options?
Thetablebelowprovidesdetailedinformationontheavailablesupportforthebuilt-incontrollersoneachHPplatform.
SoftwareRAIDusingOSRAIDcapabilityisalsoavailableforHPZTurboDrives.
System Controller options # ports Connector color RAID capability Max # of arrays
HPZ440
HPZ640
SATA(6Gb/s) 2 Black 0,1 1
sSATA(6Gb/s) 4 Dark grey 0,1,5,10 2
HPZ840
SATA(6Gb/s) 2 Black 0,1 1
sSATA(6Gb/s) 4 Dark grey 0,1,5,10 2
LSISAS(6Gb/s) 8 White 0,1,10,1E 2
HPZ230 SATA(6Gb/s) 5 Black 0,1,5 2
HPZ1 SATA(6Gb/s) 2 Black 0,1 2
Note:sSATAissometimescalledsecondarySATAorserverSATA.
Why is it recommended to use an add-in controller card (ROC) for RAID 5?
HPrecommendsusinganadd-incontrollercardRAID-On-Chip(ROC)forRAID5duetotheprocessingpowerittakesto
generatetheparitystripesusedinRAID5arrays.Ifaseparateprocessor(theROCinthiscase)isnotusedtogenerate
theparity,thehostCPUmustgeneratetheparity.UsingthehostCPUmayleadtolowerperformancethanooadingthe
parity generation to dedicated hardware.
Is TRIM supported when using RAID with SSDs?
Yes,TRIMissupportedonvariousSSDswhenusingRAID.ThetablebelowdemonstratestheplatformsandRAID
congurationsthatsupporttheTRIMoperation.
Controller Platform TRIM supported RAID levels TRIM not supported RAID levels
SATA HPZ440,HPZ640,HPZ840 0,1
sSATA HPZ440,HPZ640,HPZ840 0,1,10 5
SAS HPZ840 0,1,1E,10
SATA HPZ1 0,1
SATA HPZ230 0,1 5
MicrosoftSoftwareRAID* Any platform Spanned,striped,mirrored,RAID-5
LSI9217 HPZ440,HPZ640,HPZ840 0,1,1E,10
LSI9270 HPZ440,HPZ640,HPZ840 0,1,5,6,10,50,60
*Note:MicrosoftsoftwareRAIDcanspancontrollers(SATA,SAS,PCIe)andmixeddevicetypes(HDDs,SSDs,PCIeStorage,HPZ-Turbo).