Re: Mount options for Ext3? - Mailing list pgsql-performance

From Kevin Brown
Subject Re: Mount options for Ext3?
Date
Msg-id 20030125025008.GD28252@filer
Whole thread Raw
In response to Re: Mount options for Ext3?  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Mount options for Ext3?
Re: Mount options for Ext3?
List pgsql-performance
Josh Berkus wrote:
> Well, the only reason I use Ext3 rather than Ext2 is to prevent fsck's on
> restart after a crash.    So I'm interested in the data option that gives the
> minimum performance hit, even if it means that I sacrifice some reliability.
> I'm running with fsynch on, and the DB is on a mirrored drive array, so I'm
> not too worried about filesystem-level errors.
>
> So would that be "data=writeback"?

Yes.  That should give almost the same semantics as ext2 does by
default, except that metadata is journalled, so no fsck needed.  :-)

In fact, I believe that's exactly how ReiserFS works, if I'm not
mistaken (I saw someone claim that it does data journalling, but I've
never seen any references to how to get ReiserFS to journal data).


BTW, why exactly are you running ext3?  It has some nice journalling
features but it sounds like you don't want to use them.  But at the
same time, it uses pre-allocated inodes just like ext2 does, so it's
possible to run out of inodes on ext2/3 while AFAIK that's not
possible under ReiserFS.  That's not likely to be a problem unless
you're running a news server or something, though.  :-)

On the other hand, ext3 with data=writeback will probably be faster
than ReiserFS for a number of things.

No idea how stable ext3 is versus ReiserFS...



--
Kevin Brown                          kevin@sysexperts.com

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