Re: I have a fusion IO drive available for testing - Mailing list pgsql-performance

From Dave Cramer
Subject Re: I have a fusion IO drive available for testing
Date
Msg-id 491f66a50903310520j2d540fa9q3c0f8403bad60c14@mail.gmail.com
Whole thread Raw
In response to Re: I have a fusion IO drive available for testing  (David Rees <drees76@gmail.com>)
Responses Re: I have a fusion IO drive available for testing  (Craig James <craig_james@emolecules.com>)
List pgsql-performance


On Fri, Mar 27, 2009 at 4:33 PM, David Rees <drees76@gmail.com> wrote:
On Fri, Mar 27, 2009 at 10:30 AM,  <david@lang.hm> wrote:
> On Thu, 26 Mar 2009, Dave Cramer wrote:
>> So far using dd I am seeing around 264MB/s on ext3, 335MB/s on ext2 write
>> speed. So the question becomes what is the best filesystem for this drive?
>
> until the current mess with ext3 and fsync gets resolved, i would say it
> would probably be a bad choice. I consider ext4 too new, so I would say XFS
> or ext2 (depending on if you need the journal or not)

If you're worried about the performance implications of ext3 in
data=ordered mode, the best thing to do is to mount the filesystem in
data=writeback mode instead.

If you're only using the filesystem for PostgreSQL data or logs, your
data will be just as safe except now that data and metadata won't be
forced to disk in the order it was written.

And you still get the benefit of a journal so fsck's after a crash will be fast.

XFS probably is a decent choice, but I don't have much experience with
it except on a desktop system where I can tell you that having write
barriers on absolutely kills performance of anything that does a lot
of filesystem metadata updates.  Again, not a big concern if the
filesystem is only being used for PostgreSQL data or logs.

-Dave

So I tried writing directly to the device, gets around 250MB/s, reads at around 500MB/s

The client is using redhat so xfs is not an option.

Dave

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