Subject: Re: [HACKERS] Large databases, performance
From: Greg Copeland <greg@CopelandConsulting.Net>
To: shridhar_daithankar@persistent.co.in
Cc: pgsql-general <pgsql-general@postgresql.org>,
	PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org>
In-Reply-To: <3D9CB613.1700.A7DEEF0@localhost>
References: <Pine.LNX.4.21.0210031353540.26902-100000@ponder.fairway2k.co.uk>
	<3D9CB613.1700.A7DEEF0@localhost>
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Date: 03 Oct 2002 11:23:28 -0500
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On Thu, 2002-10-03 at 10:56, Shridhar Daithankar wrote:
> Well, we were comparing ext3 v/s reiserfs. I don't remember the journalli=
ng=20
> mode of ext3 but we did a 10 GB write test. Besides converting the RAID t=
o RAID-
> 0 from RAID-5 might have something to do about it.
>=20
> There was a discussion on hackers some time back as in which file system =
is=20
> better. I hope this might have an addition over it..


Hmm.  Reiserfs' claim to fame is it's low latency with many, many small
files and that it's journaled.  I've never seem anyone comment about it
being considered an extremely fast file system in an general computing
context nor have I seen any even hint at it as a file system for use in
heavy I/O databases.  This is why Reiserfs is popular with news and
squid cache servers as it's almost an ideal fit.  That is, tons of small
files or directories contained within a single directory.  As such, I'm
very surprised that reiserfs is even in the running for your comparison.

Might I point you toward XFS, JFS, or ext3, ?  As I understand it, XFS
and JFS are going to be your preferred file systems for for this type of
application with XFS in the lead as it's tool suite is very rich and
robust.  I'm actually lacking JFS experience but from what I've read,
it's a notch or two back from XFS in robustness (assuming we are talking
Linux here).  Feel free to read and play to find out for your self.  I'd
recommend that you start playing with XFS to see how the others
compare.  After all, XFS' specific claim to fame is high throughput w/
low latency on large and very large files.  Furthermore, they even have
a real time mechanism that you can further play with to see how it
effects your throughput and/or latencies.

Greg


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