dovecot - Mar 2008 - Dovecot / FreeBSD / Nfs mailstore / Index=memory

Hello,

I have recently changed imap from Courier-imap to dovecot because of  
serial problems with courier-imap, I have being forced to do it very  
quickly... and without extensives tests.

I have 3 mails servers (freebsd based) behind a load balancer and a  
nfs mailstore on a netapp.

On my first tests I have setup the index into some nfs shared mount,  
but it seems that some imap clients are going mad when deleting files  
(mostly because they do open some new imap connection and the index  
was not clean) so I have changed index to memory.

This has fixed one of my problems.

Now I have some strange problems is that NFS activity passed from  
about... 5mbps to more than 70Mpbs...

Is there any reasons about that ?

OS: FreeBSD 6.2-p11 / x86
Dovecot : 1.0.13 (freebsd ports)
Auth: ldap based

Nfs mail spool :
filer:/vol/vol0/mail       /var/mailusers  nfs      
rw,nfsv3,mntudp,bg,noatime,nolockd      0 0

Thanks,
/Xavier

On Wed, 2008-03-19 at 09:13 +0100, Xavier Beaudouin
wrote:
> Hello,
> 
> I have recently changed imap from Courier-imap to dovecot because of  
> serial problems with courier-imap, I have being forced to do it very  
> quickly... and without extensives tests.
> 
> I have 3 mails servers (freebsd based) behind a load balancer and a  
> nfs mailstore on a netapp.
> 
> On my first tests I have setup the index into some nfs shared mount,  
> but it seems that some imap clients are going mad when deleting files  
> (mostly because they do open some new imap connection and the index  
> was not clean) so I have changed index to memory.
> 
> This has fixed one of my problems.
Best solution would be to use v1.1 and its mail_nfs_*=yes settings. They
make Dovecot work very well with NFS.
> Now I have some strange problems is that NFS activity passed from  
> about... 5mbps to more than 70Mpbs...
Do you use also POP3? Other than that I can't think of why it would give
worse performance than Courier.

Also have you read http://wiki.dovecot.org/NFS?

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Timo Sirainen wrote:
> On Wed, 2008-03-19 at 09:13 +0100, Xavier Beaudouin wrote:
>> Hello,
>>
>> I have recently changed imap from Courier-imap to dovecot because of  
>> serial problems with courier-imap, I have being forced to do it very  
>> quickly... and without extensives tests.
>>
>> I have 3 mails servers (freebsd based) behind a load balancer and a  
>> nfs mailstore on a netapp.
>>
>> On my first tests I have setup the index into some nfs shared mount,  
>> but it seems that some imap clients are going mad when deleting files  
>> (mostly because they do open some new imap connection and the index  
>> was not clean) so I have changed index to memory.
>>
>> This has fixed one of my problems.
> 
> Best solution would be to use v1.1 and its mail_nfs_*=yes settings. They
> make Dovecot work very well with NFS.
We're using v1.1rc3 in production, with indexes on NFS, and performance 
has never been better.  Before 1.1 we too had to use index=memory, which 
caused SORT on large (4k+ messages) mailboxes to take up to a minute. 
Now it takes 1-2 seconds.

-Rich