[Dovecot] Dovecot write activity (mostly 1.1.x)

[Timo Sirainen]

On Sun, 2007-11-04 at 14:10 +0100, mikkel at euro123.dk wrote:
> >> Write activity is about half that of read activity when measuring
> >> throughput. But when measuring operations it’s about 5-7 times as high
> >> (measured with
> >> zpool iostat on ZFS).
> >
> > Have you tried with fsync_disable=yes? ZFS's fsyncing performance
> > apparently isn't all that great. I'm guessing this is also the reason for
> > the I/O stalls in your other mail.
> >
> 
> I'm using fsync_disable=yes already.

Well, if you use only clients that don't really need indexes they could
just slow things down. You could try disabling indexes to see how it
works then (:INDEX=MEMORY to mail_location).

Although v1.1 should be writing less to disk than v1.0, because v1.1
doesn't anymore update dovecot.index as often. v1.1 versions before
beta6 had some problems updating cache file though. They could have
updated it more often than necessary, and beta5 didn't really even
update it at all.

> (Possibly this is also the answer to my other post regarding
> stalled/delayed I/O)

You could truss the hanging process to see what it's doing.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : http://dovecot.org/pipermail/dovecot/attachments/20071104/cefcf1b8/attachment.bin