On Thu, Jun 15, 2000 at 01:05:43PM +0100, Paul Jakma wrote:
> On Thu, 15 Jun 2000, Paul Trainor wrote:
> > AMI Megaraid should do the job.
> what sort of performance do they give? from what i've seen on linux-raid
> they're dreadfully dreadfully slow, esp. at RAID5.
I recommend the AMI megaraid 1500 elite. They *rock*. 128MB battery backed
cache. Dell call it a "PERC 2/DC". It came in a Dell 2450 (which I
recommend for your mail box, Colm, btw. Even two cpus is overkill for
outgoing mail - but about right/not enough if you're delivering mail
locally, doing imap and/or even hosting webmail on the same box.)
I have done quite a few benchmarks on the 2450 with 1500raid...
Machine with 2GB ram, four 18GB 10k disks as a raid5 array with 128kB
"bits" (*). LVM. Then ext2 filesystems async, 4kB blocks, stride=32,
bonnie++ results with dataset of 4GB...
Version 0.99e ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine MB K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
Unknown 4096 9789 99 30189 20 12476 21 9536 95 42929 30 5.4 0
------Sequential Create------ --------Random Create--------
-Create-- --Stat--- -Delete-- -Create-- --Stat--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
30 196 99 642 99 6978 100 197 99 826 100 796 97
All the other AMI raid cards I've seen are good only for landfill. This
one kicks bottom. :-)
(*) Sorry, AMI's documentation doesn't make it clear whether it's 128kB
over $n$ disks or per disk. ie. chunks or stripes. Like I care.
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