Software vs Hardware RAID

[bene-Gk2boCrsRs1AfugRpC6u6w at public.gmane.org (Ben Eisenbraun)]

On Fri, May 25, 2007 at 12:52:26PM -0400, Dan Ritter wrote:
> Software RAID: cheap, fast, reliable. No hot swaps, but you can
> put in a spare disk.

I think hot swaps are more a function of the chassis and of the 
disk type than of the RAID implementation, since I've done hot 
swaps on software RAID with SATA before.

> Hardware RAID: two subsets: real HW RAID, and fake HW RAID.
> 
> Fake HW RAID: cheap, slow, unreliable. No hot swaps. Probably no
> spare disks.

The other thing I would point out is that this is a continuum.  On the 
one end you have "L00K R at 1D F at ST $19" and on the other end you have 
$1000+ multi-channel SCSI RAID cards.

The intermediate steps tend to be IDE or SATA based.  Some have 
dedicated CPUs to do their math and some offload to the system CPU.
The quality of the BIOS in these cards also varies widely 
depending on manufacturer and sometimes even on the card model 
itself.

> Real HW RAID: expensive, fast, reliable. Hot swaps! And spare
> disks, too.

-b

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s/[0-9a-zA-Z]/42/g                                          <hop>

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