[Dovecot] Dovecot + DRBD/GFS mailstore

[Romer Ventura]

Last time i checked the free version of DRBD only supports 2 nodes.  
The paid version supports 16 nodes. This however, doesnt mean that  
you cannot use the storage via NFS or SMB/CIFS mount point. Only that  
the DRBD replication will only happen to 2 nodes. If a third node is  
supported on the free version, it would be for quorum only.

They might have changed it since, but i doubt it.

On Aug 24, 2009, at 10:51 AM, Eric Jon Rostetter wrote:

> Quoting Guy <wyldfury at gmail.com>:
>
>> I'm looking at the possibility of running a pair of servers with
>> Dovecot LDA/imap/pop3 using internal drives with DRBD and GFS (or
>> other clustered FS) for the mail storage and ext3 for the root drive.
>
> I'm in testing right now with this setup.  Two Dell PE 2900 servers
> (quad core @ 2.3 GHz, 8 GB RAM, raid 10 for the GFS+DRBD disk, raid 1
> for the ext3 disks).  Running DRBD as a master/master setup.
>
> I added a third node for webmail (Dell PE 2650), but it doesn't do the
> DRBD or GFS.  It is there mostly to make a 3-node cluster versus 2- 
> node
> cluster, to avoid split-brain type situations.  And of course to do  
> the
> webmail. :)
>
> Using MailScanner as the MTA, dovecot for pop/imap, mailman for  
> mailing
> lists, Horde/IMP/etc for webmail.   All held together with RHCS on  
> CentOS
> 5.3.
>
> All services run on only one node at a time, with failover...  This  
> may
> or may not help with GFS lock contention (not for /var/spool/mail,  
> since
> it is always accessed from both nodes at once, but yes for dovecot  
> indexes
> since they are only ever accessed on one node at a time, etc).   
> This is
> probably where performance will really be decided (GFS lock  
> contention).
>
> Cluster Status for mailer @ Mon Aug 24 10:27:12 2009
> Member Status: Quorate
>
>  Member Name                             ID   Status
>  ------ ----                             ---- ------
>  mailer1-hb.localdomain                      1 Online, rgmanager
>  mailer2-hb.localdomain                      2 Online, Local,  
> rgmanager
>  webmail1-hb.localdomain                     3 Online, rgmanager
>
>  Service Name                   Owner (Last)                   State
>  ------- ----                   ----- ------                   -----
>  service:Apache                 mailer1-hb.localdomain         started
>  service:Dovecot                mailer1-hb.localdomain         started
>  service:MailMan                mailer2-hb.localdomain         started
>  service:MailScanner            mailer2-hb.localdomain         started
>  service:VIP-MAIL               mailer1-hb.localdomain         started
>  service:VIP-SMTP               mailer2-hb.localdomain         started
>  service:WebMail                webmail1-hb.localdomain        started
>
>> Has anyone had experience with a setup like the one I'm suggesting?
>> What was performance like with Dovecot using GFS?
>
> So far it is early testing.  63 users, but only about 12 of those are
> "power users".  The performance has been real good so far, but as I  
> say,
> not many users yet.
>
> My GFS is sharing the mail log files (via syslog-ng, what would  
> otherwise
> be /var/log/maillog), the dovecot index files, the /var/spool/mail/  
> mbox
> spool (yes, I use mbox), and "shared" configuration files for the  
> two nodes
> (mailman data, MailScanner/Sendmail configs, dovecot config, clamav/ 
> spamd
> config, procmail config, apache config, ssl certificates, etc).
>
> If interested, I can let you know about performance once I know  
> more...
>
>> Thanks
>> Guy
>
> -- 
> Eric Rostetter
> The Department of Physics
> The University of Texas at Austin
>
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