http://stats.distributed.net is setup with the OS, WAL, and temp on a
RAID1 and the database on a RAID10. The drives are 200G SATA with a
3ware raid card. I don't think the controller has battery-backed cache,
but I'm not sure. In any case, it's almost never disk-bound on the
mirror; when it's disk-bound it's usually the RAID10. But this is a
read-mostly database. If it was write-heavy, that might not be the case.
Also, in general, I see very little disk activity from the OS itself, so
I don't think there's a large disadvantage to having it on the same
drives as part of your database. I would recommend different filesystems
for each, though. (ie: not one giant / partition)
On Tue, Apr 19, 2005 at 06:00:42PM -0700, Jeff Frost wrote:
> Now that we've hashed out which drives are quicker and more money equals
> faster...
>
> Let's say you had a server with 6 separate 15k RPM SCSI disks, what raid
> option would you use for a standalone postgres server?
>
> a) 3xRAID1 - 1 for data, 1 for xlog, 1 for os?
> b) 1xRAID1 for OS/xlog, 1xRAID5 for data
> c) 1xRAID10 for OS/xlong/data
> d) 1xRAID1 for OS, 1xRAID10 for data
> e) .....
>
> I was initially leaning towards b, but after talking to Josh a bit, I
> suspect that with only 4 disks the raid5 might be a performance detriment
> vs 3 raid 1s or some sort of split raid10 setup.
>
> --
> Jeff Frost, Owner <jeff@frostconsultingllc.com>
> Frost Consulting, LLC http://www.frostconsultingllc.com/
> Phone: 650-780-7908 FAX: 650-649-1954
>
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Jim C. Nasby, Database Consultant decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828
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