RAID: Software vs. Hardware

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The difference between software and hardware RAID solutions.
1) Software RAID is implemented by the host computer and require CPU time. This could affect performance, depending on how much spare CPU time the system has.

Hardware RAID is independent of the host system and takes no CPU time.


2) Hardware RAID is implemented by a separate RAID card in an expansion slot. It has it's own CPU and may have DRAM, ROMs, and internal buses all for the RAID. The SCSI overhead is higher, which may decrease performance.

Software RAID uses the CPU of the host system for RAID control and has a lower SCSI overhead.


3) The lower RAID levels (0 and 1) are best done with software.

Higher RAID levels (3 and 5) work better with a hardware solution.


Machines Affected: PowerTower Pro with RAID
Published Date: Feb 18, 2012