Date: Fri, 4 Aug 2006 15:44:50 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: "J. Andrew Rogers" <jrogers@neopolitan.com>,
 Milen Kulev <makulev@gmx.net>,
	"Pgsql-Performance ((E-mail))" <pgsql-performance@postgresql.org>
Subject: Re: XFS filessystem for Datawarehousing
Message-ID: <20060804204450.GS40481@pervasive.com>
References: <012d01c6b5b4$6db33680$0a00a8c0@trivadis.com>
	<D986D872-2CE4-4D12-B368-2F4494CFE08B@neopolitan.com>
	<20060802004223.GE20401@alvh.no-ip.org>
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On Tue, Aug 01, 2006 at 08:42:23PM -0400, Alvaro Herrera wrote:
> J. Andrew Rogers wrote:
> > 
> > On Aug 1, 2006, at 2:49 PM, Milen Kulev wrote:
> > >Is anyone using XFS for storing/retrieving relatively large amount  
> > >of data  (~ 200GB)?
> > 
> > 
> > Yes, we've been using it on Linux since v2.4 (currently v2.6) and it  
> > has been rock solid on our database servers (Opterons, running in  
> > both 32-bit and 64-bit mode).  Our databases are not quite 200GB  
> > (maybe 75GB for a big one currently), but ballpark enough that the  
> > experience is probably valid.  We also have a few terabyte+ non- 
> > database XFS file servers too.
> > 
> > Performance has been very good even with nearly full file systems,  
> > and reliability has been perfect so far. Some of those file systems  
> > get used pretty hard for months or years non-stop.  Comparatively, I  
> > can only tell you that XFS tends to be significantly faster than  
> > Ext3, but we never did any serious file system tuning either.
> 
> Most likely ext3 was used on the default configuration, which logs data
> operations as well as metadata, which is what XFS logs.  I don't think
> I've seen any credible comparison between XFS and ext3 with the
> metadata-only journal option.
> 
> On the other hand I don't think it makes sense to journal data on a
> PostgreSQL environment.  Metadata is enough, given that we log data on
> WAL anyway.

Actually, according to http://en.wikipedia.org/wiki/Ext3 the default
journalling option for ext3 isn't to journal the data (which is actually
data=journal), but to wait until the data is written before considering
the metadata to be committed (data=ordered).
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461