Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[bert hubert]

On Sun, Dec 28, 2003 at 01:35:35PM -0800, Johannes Ruscheinski wrote:

> Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> hardware raid capability of the Promise tx4000 and if we'd use software
> raid instead, what would be the CPU overhead?

For the cost differential between linux native RAID and an external device
of similar capabilities, outfit yourself with an additional CPU. I don't use
RAID5 a lot but to a modern CPU, checksumming dozens of megabytes/second is
child's play:

raid5: measuring checksumming speed
   8regs     :  1479.600 MB/sec
   32regs    :   744.400 MB/sec
   pIII_sse  :  1649.200 MB/sec
   pII_mmx   :  1806.000 MB/sec
   p5_mmx    :  1915.200 MB/sec
raid5: using function: pIII_sse (1649.200 MB/sec)

This is on a 800MHz Celeron, so a recent >2Ghz system will do lots better
still.

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