From: Simon Riggs <simon@2ndquadrant.com>
To: Josh Berkus <josh@agliodbs.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgreSQL.org, pgsql-novice@postgreSQL.org, Mija Lee <mija@scharp.org>
Subject: Re: PG on NFS may be just a bad idea
Date: Mon, 01 Oct 2007 19:36:54 +0100
Message-ID: <1191263814.4260.57.camel@ebony.site> (raw)
In-Reply-To: <47012AC5.9040808@agliodbs.com>
References: <25517.1191038302@sss.pgh.pa.us>
<47012AC5.9040808@agliodbs.com>
On Mon, 2007-10-01 at 10:13 -0700, Josh Berkus wrote:
> > Maybe we need to actively discourage people from running Postgres
> > against NFS-mounted data directories. Shane Kerr's paper cited above
> > mentions some other rather scary properties, including O_EXCL file
> > creation not really working properly.
>
> Wouldn't you be describing a Linux-specific issue, though? And possibly
> kernel-specific?
Possibly, though if you have any specific refutations of the Kerr paper
then it would be a good idea to air them. It isn't enough to just hint
some exist.
> It's hard to reconcile this with the real-world performance of
> PostgreSQL on NFS, which is happening all over the place. Most notably,
> Joe Conway's 20,000 txn/sec.
>
> I *do* think it's an accurate statement that if you're going to use
> Postgres, or any other OLTP database, on NFS you'd better have access to
> a NAS expert. But to say that it's a bad idea even if you have expert
> help is probably going to far.
I can see many papers on database performance on NFS, but I don't see
any discussion of potential reliability concerns. If anybody sits near
an NAS expert, it would be great to have that discussion.
I have found some comments that other databases require "specific
configuration settings to ensure efficient and correct usage" of NFS "to
access NAS storage devices".
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com
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Cc: simon@2ndquadrant.com, josh@agliodbs.com, tgl@sss.pgh.pa.us, mija@scharp.org
Subject: Re: PG on NFS may be just a bad idea
In-Reply-To: <1191263814.4260.57.camel@ebony.site>
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