[Dovecot] Corrupted index cache file and high CPU usage

[hydra]

Hello Timo, thank you for the reply. I was suspecting the same. However:
- the machine runs under Vmware,
- I've tried 3 different kernel versions,
- I've tried 3 different SCSI controllers.

All same results.


On Wed, Dec 21, 2011 at 6:16 PM, Timo Sirainen <tss at iki.fi> wrote:

> On 21.12.2011, at 18.38, hydra wrote:
>
> > I suspect, that dovecot v2.0.16 under Linux (tested on Gentoo 3.0.4
> > Hardened, Gentoo 3.0.6, Gentoo 3.1.4) causes 100% cpu utilization when
> > index.cache is broken and doveadm is lanched. Dovecot uses LDAP as the
> > userdb and provides IMAP and LDA. Because each user has a quota, the
> > doveadm's expunge functionality is used to get rid of old trashed mail.
> >
> > The mail log:
> > Dec 12 07:38:59 www dovecot: imap(user): Error: Corrupted index cache
> file
> > /var/data/mail/domain.tld/user/mail/dovecot.index.cache: invalid record
> size
>
> OK..
>
> > Mail is stored on ext4 and flush will use all of the CPU capacity like
> this:
> > load average: 4.00, 4.01, 4.05
> >
> > ps:
> > root     26401 98.2  0.0      0     0 ?        R    Dec20 1369:49
> > [flush-253:1]
>
> That's a kernel process..
>
> > I suspect, that this is something to do with Dovecot, because after
> > deleting the dovecot.index.cache file, everything went back to normal.
> When
> > this happens, I cannot unmount the drive nor a system reboot works.
>
> That's a kernel bug..
>
> I think you're thinking it the wrong way: Dovecot isn't causing your
> system to break. Your system is causing Dovecot to break. Faulty hardware
> or faulty kernel.