Re: EIO AP-1680 ATA133 RAID PCI Controller

[Gregory Leblanc <gleblanc@linuxweasel.com>]

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On Tue, 2003-02-11 at 09:16, Steven Dake wrote:
> I don't know the specifics of those cards, but if they include an i/o 
> processor, they are a hardware RAID.
> 
> Keep in mind that unless you want to boot or use a RAID 5, or want to 
> share your RAID volumes between different operating systems, there is 
> little reason to purchase a hardware RAID card.  Software RAID is quite 
> sufficient for most needs and the host processor running at 2+ ghz is 
> much better at RAID then a 60 mhz i960 IOP.  Keep in mind, though, that 
> hardware RAID adaptors have built in xor accelerators which can do 
> multiple xors in one instruction in hardware, allowing for much better 
> xor performance then the intel or ppc processor can do.

While the performance of RAID 5 using software RAID is generally far
superior to that provided by hardware RAID, host CPU usage can be
-quite- high in high-load situations.  The benchmarks recently posted
had cpu usage numbers at over 90% on most sequeential writes and reads.
	Greg

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