Implement Cyrus IMAPD in High Load Enviromment

[Ciro Iriarte]

2009/9/28 Lucas Zinato Carraro <lucaszc at gmail.com>:
> Hi, I am deploing cyrus-imapd in my organization:
>
> My organization need to have:
>
>  - 75000  maiboxes
>  - 10000 simultaneous connections (IMAP)
>  - 3000 mailboxes with 1Gb and 65000 with 200Mb
>  - 12 Tb for spool ( EMC Clarion Storage )
>  - 15 servers with Xeon 2.6ghz - 8gb RAM
>  - GNU/Linux 2.6 for Operating System ( RedHat, Debian etc ... )
>  - ~ 150000 messages / day
>  - Postfix as MTA
>
> I made several tests  to choose filesystem.
>  Cluster FS( gfs, ocfs ),  ext3, ext4 , reiserfs , xfs and etc..

I'm really interested in this part, do you have any test numbers to
share?, I would like to use OCFS2 for Active/Active configuration, was
it that bad?. Was ext3 faster than reiserfs?, I would though it should
be the other way around.

> my choice
>
> ext3  with   dir_index, noatime, nodiratime
>
> and partition my  problem with Cyrus Murder.
>
> My doubts are:
>
> - Exist a recommended number of conections to a front end server ?
> ( a parameter in sysctl.conf in GNU/Linux )
>
> - Exist a recommended size to a Backend server ( Ex: 1 Tb )?
>
> Cyrus IMAP works great with large mailboxes an billions of small files.
> Backup is my big problem.
>
> - Exist any solution better than make a SNAPSHOT of STORAGE and backup all
> file system (/dev/sdaX ) ?

It's the best approach. Depends on your backup tool, there are
comercial tools that allow you to backup at the filesystem level
(filesystem image) and restore at the file level. That would be a lot
faster than backing up the files per se.

>
> I know that performance is  terrible with billions of small files, and make
> tests using tar . (  ex: a.tar.gz = /var/spool/imap/a/ ), this approach
> increase the performance with my LTO tapes.
>
> Anyone has another suggestion  ?
>
>
> Regards,
> Lucas Zinato Carraro
>

Regards,

-- 
Ciro Iriarte
http://cyruspy.wordpress.com
--