> > I've done a few tests.
> >
> > Remounting the fs where $PGDATA lives with "forcedirectio"
> > (together with logging, that is default) did not help
> > (if not harm...) performance.
> >
> >
>
> Sure - forcedirectio on the entire $PGDATA is a definite loss, you only
> want it on $PGDATA/pg_xlog. The usual way this is accomplished is by
> making a separate filsystem for pg_xlog and symlinking from $PGDATA.
>
> Did you try the other option of remounting the fs for $PGDATA without
> logging or forcedirectio?
not yet, I'm not on the final disk set yet.
when I get there I'll have two separate filesystems for pg_xlog and base
and will try what you suggest.
(but note the other mail about wal_sync_method = fsync)
bye, chris.