[Dovecot] Sudden, large numbers of "Timeout while waiting for lock for transaction log ..."

[Jack Stewart]

Timo Sirainen wrote:
> On Wed, 2009-01-07 at 08:32 -0800, Jack Stewart wrote:
> 
>> Timo Sirainen wrote:
>>> On Tue, 2009-01-06 at 23:11 -0800, Jack Stewart wrote:
>>>> an  6 01:21:02 earth-griffen dovecot: IMAP(zabala): Timeout while 
>>>> waiting for lock for transaction log file 
>>>> /var/spool/dovecot/indexes/z/zabala/.INBOX/dovecot.index.log
>>> This is the main problem. So indexes are also on NFS? What locking are
>>> they using (dovecot -n output)?
>>>
>> Yes, the indexes are also on NFS.
>>
>> The locking is fcntl() - the default.
> 
> I'm guessing that's the problem. NFS locking seems to break/hang
> randomly sometimes. Can you somehow restart the NFS server locking
> daemon?
> 

restarting the server would be tough but I'll see what can be done. It's 
an EMC Celerra with head failover so in theory it should be straight 
forward.

There is another red flag. The Celerra is configured for snapshots and 
the problem started around the time one of the snapshots occurred. I'm 
fairly sure that the snapshots use file or volume locking.