Disk IO issues

[Mike McGrath]

On Sat, 3 Jan 2009, Matt Domsch wrote:

> On Sun, Jan 04, 2009 at 03:02:55AM +0000, Kostas Georgiou wrote:
> > On Sat, Jan 03, 2009 at 06:32:38PM -0600, Matt Domsch wrote:
> >
> > > What ext3 journaling options are enabled (e.g. what does 'mount' say)?
> > > If it's data=ordered (the default), that's OK.  If it's data=journal,
> > > then all the data gets written twice (first to the journal, then the
> > > journal to the disk), which is really really slow, and the size of the
> > > journal would really make a difference too.
> >
> > For an NFS server (assuming that you aren't exporting as async)
> > data=journal can give you better performance than anything else
> > actually. The NFS howto has a brief note in the performance section
> > about this.
>
> Yes, if the slowness is seen by applications on the client side of the
> NFS server, data=journal on the NFS server can help.
>
> Mike, your tests were all on the local file system, not across an NFS
> connection, right?
>

Correct, though (obviously) we're seeing the slownees remotely as well.

	-Mike