On Tue, 16 Mar 2010 19:00:52 +0100, martin f krafft <madduck@madduck.net> wrote:
> I use ext4 with data=ordered, and while notmuch is writing the
> Xapian database, most I/O stalls on the machine:
> 
>   - Firefox does not get any mouse events
>   - Vim blocks writing the viminfo file
>   - All disk operations queue for multiple seconds.
> 
> So no, ext4 is not a solution. Is it just me, or should no
> filesystem of this world be able to hog a system this badly? I think
> the culprit is the IO-scheduler.
> 
In my uninformed opinion, I think it more likely that the dominant factor is
the page reclaim code. Even noop scheduling is pretty bad.

- Ben