Jim C. Nasby wrote:
> On Tue, Aug 01, 2006 at 08:42:23PM -0400, Alvaro Herrera wrote:
> > 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).
Well, we don't need the data to be written before considering metadata
committed. data=writeback is enough for partitions to be dedicated to
PGDATA. Not sure what other FSs do on this front but the ext3 default
leans towards safe rather than speedy.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
