[Gllug] A SATA Raid card worth having?

[Nix]

On Tue, 31 Jan 2006, M. Blackmore uttered the following:
> Err, ok, on a 400mhz spare old computer to run a home fileserver (and
> its inheritors as handmedowns occur) is it worth running a hardware raid
> or should I just stick with software raid?

Well as of last week I'm using software RAID on my PIII/600, across two
IDE disks and a SCSI (well, one IDE disk and part of another IDE disk
and part of a SCSI disk): I can't see any slowdown to speak of. It's a
bit fiddly getting the initramfs set up if you want to RAID the root
filesystem, and if you RAID swap and swap a lot you might well see
slowdowns --- but TBH if you're hitting swap anyway you've got such a
slowdown that a slight increase in CPU consumption from parity
computations isn't going to cost you much at all.

md tells you at startup how fast its chosen parity checker is. Mine
says:

raid5: using function: pIII_sse (1208.800 MB/sec)

and, well, no disk I've ever heard of has that sort of bandwidth, and no
collection of disks you could reasonably hang off a PC does either
(what, that's 30 disks at 40Mb/s, and that's also way above PCI bus
bandwidth...)

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