Re: RAID suggestions?
On Tue, Mar 18, 2008 at 03:56:00PM -0400, Michael S. Peek wrote:
> But now I'm looking to build replacement servers and I thought I would
> ask what the community uses for it's hardware RAID, and why?
I only use hardware raid where a battery-backed-up ram cache is available
and the performance enhancement in confers is required (ie the mail
storage for a mail server, a file server that sees a /lot/ of writes,
etc). This is about the only time I would give up the flexibility of linux
s/w raid.
If you are doing only occasional writes and alot of reads then good
controllers+sw raid+a buttload of ram will do you IMO. You get the
joyous flexibility of mdadm for managing your raid array and the system
ram acts as your fs cache for your many reads.
You should also be careful with hw raid. The cheap stuff may well be
worse then going sw. One server model that I use I turn off the hw raid
on it because after a bit of testing it showed that sw raid was winning
out in terms of performance.
As for reliability of sw raid, I've been using it on 30 servers for 3
years without a hitch. It's handled disk failures just fine (and in one
case the crashing of a mb northbridge locking up the pc - array
recovered without problems). The other part of this is that you are not
locked into a single vendor (or even model) for your array. If your raid
card dies (it happens) it may well mean a complete rebuild unless you
can find another like it. With software raid you can mix and match
controllers, hd types and even network hds and it'll just deal.
Hope this helps. :)
cat.
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