Re: Looking for a cheap upgrade (RAID)

On Fri, 2 May 2003, Josh Berkus wrote:

> Scott,
>
> > With that setup, you'd have 15 Gigs for the OS, 4 gigs for swap, and about
> > 300 gigs for the database.  The nice thing about RAID 5 is that random
> > read performance for parallel load gets better as you add drives.  Write
> > performance gets a little better with more drives since it's likely that
> > the drives you're writing to aren't the same ones being read.
>
> Yeah, but I've found with relatively few drives (such as the minimum of 3)
> that RAID 5 performance is considerably worse for writes than RAID 1 -- as
> bad as 30-40% of the speed of a raw SCSI disk.   This problem goes away with
> more disks, of course.

Yeah, My RAID test box is an old dual PPro 200 with 6 to 8 2 gig drives in
it and on two seperate scsi channels. It's truly amazing how much better
RAID5 is when you get that many drives together.  OF course, RAID 0 on
that setup really flies. :-0

I'd have to say if you're only gonna need 50 or so gigs max, then a RAID1
is much easier to configure, and with a hot spare is very reliable.