Re: IOzone testing

["Jérôme Poulin" <jeromepoulin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Sat, Sep 26, 2009 at 8:13 AM, Jeff Layton <laytonjb-fOdFMYwuEsI@public.gmane.org> wrote:
> Good morning,
>
> I'm running IOzone on a NILFS2 partition and it's running alot
> slower that I had expected. I'm pretty sure it's because of the
> checkpoints. I can change the protection_period to something
> very small (or zero). Would that improve the performance?
>
The protection period only affects how the cleaner daemon will clean
the old checkpoints, if 0 I guess it will just clean them up as soon
as it can but it won't stop creating them. You could, just for
benchmark purpose, kill nilfs_cleanerd which will stop checkpoint
related activities.

> In addition, is there a way to turn off checkpointing?
>
The whole filesystem is based on those checkpoint, the fact that it is
a log filesystem makes it so all writes are made at the end of the
device, and when a write is complete, a checkpoint is made.

> Thanks!
>
> Jeff