[Dovecot] Load spikes on NFS server, multiple index updaters.

[Timo Sirainen]

On Aug 25, 2009, at 11:39 PM, Jorgen Lundman wrote:

>> Do you need Maildir++ quota at all? With v1.2 you could use dict  
>> quota with file backend. It'll use dovecot.index.cache when  
>> recalculating quota, although it doesn't do that unless the quota  
>> is lost for some reason (so about never).
>
> We only needed a temporary solution. Long term, we have already  
> tested ZFS's user-quota, and this is where we will go. Getting  
> enough momentum to get the process started (management...) is what  
> has been frustrating. Would you say this trouble is soft-quotas  
> scanning, and not just generic index rebuild?

The problem is Maildir++ quota implementation. I did it exactly as  
Courier's specs said it should be done.. It doesn't use Dovecot's  
indexes at all, so I could get rid of this problem by changing it to  
use indexes. But that'll complicate the code and makes it more or less  
what the dict quota with file backend does already..

> The reason I ask is that; if it is related to quotas, that gives me  
> yet-another reason to move to zfs quotas (and the trouble will go  
> away). If it is normal index rebuilding, it will still happen even  
> after using ZFS quotas.


Yeah, zfs quotas gets rid of this problem. Maybe I should also start  
recommending people to use dict quota with v1.2.. Hmm. Although I  
think there was also some rare issue with it that I should fix.