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Re: Optimal Postgres setup with 6 disks total (including OS)

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On 06/12/2006, at 10:39 PM, Craig Sanders wrote:
for testing, stick in a smallish boot drive (whatever you have spare)
and install debian on it. then reconfigure the raid disks in various
ways (and formatted using various filesystems - ext3, xfs, reiser,
whatever) and run bonnie++ on it each time.

Bonnie is great for testing throughput but not really a great test for
every database.

should take about a day or so to run all the tests....but well worth it.

Actually - to run proper tests will probably take much longer - but agreed,
it is definitely worth it.

for a long-lived server, this is pretty much the only way to guarantee
getting the best performance. in theory, raid 1+0 should beat raid 5,
but practice has a way of trumping theory every time.

RAID 1+0 is great if you have a lot of data which needs to be streamed, (full
table scans) but for Random access, it is not really better than a well
implemented Raid 1.

You will probably find that you are better off running two raid 1s and separating
your data across multiple disks than you are running one raid 1+0.

You may also want to look at putting your indexes on different physical disks as well.

We are currently 4x raid 1s for data, 1x raid 1 for indexes and 1x raid 1 for the xlog.


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