Recomendations for a 15000 Cyrus Mailboxes

[Rudy Gevaert]

Nestor A. Diaz wrote:

> These are the plans: (comments on every number will be apreciated)

I (at Ghent university) use:

> 
>   1. Linux LVM over a 600 GB RAID 10 ( 4 x 300 GB)

An EMC CX400 and CX500, with fibre channel and ata disks.  12 luns are 
400 GiG raid 5, 6 of them on FC disks (primairy) and 6 of them on ATA 
disks (replica).  An other lun is 50 gig (more later) on FC disks.  Each 
lun is currently uses 50% of disk space.

>   2. Which filesystem seems to be the better ? ext3 ? xfs ? reiserfs ?

We are using xfs.

>   3. Which options to format the filesystem ? acording to the chosed
>      filesystem

nothing special.

>   4. Which pop3 / imap proxy to use ?

we use perdition

>   5. Single instance or multiple instances of cyrus ? taking in mind
>      that there should be the option to recover a mailbox or some mail
>      of a mailbox without having to shut down the whole cyrus system.

We have currently 7 backends, three on site A and four on site B. 
(backend 7 is special).   6 backends are replicated.  So each each 
physical machine is running a primary backend and a replicated backend.
For now backend 7 isn't replicated.

>   6. Best way to perform backups ? LVM snapshots ? shutting down some
>      cyrus partitions ? RAID10 hot swap ?

We run delayed expunge and backup to tape.

>   7. Any other suggestion will be welcome.

We use postfix to delivery via lmtp over tcp to the backends.  All 
information is stored in an openldap directory server.  Each mailrelay 
and physical mailstore machine (that has a primary and replica) runs an 
openldap replica.  We use saslauthd to authorize the users.  We run 
cyrus with virtual domain support.

I'm currently setting up backend 7 that will run a patched saslauthd 
that supports multiple passwords per user.

The users are divided over the backend like this:

+-----------------+----------+
| count(mailhost) | mailhost |
+-----------------+----------+
|           20857 | mail1    |
|            1292 | mail2    |
|            3237 | mail3    |
|           20926 | mail4    |
|            1339 | mail5    |
|            3296 | mail6    |
+-----------------+----------+


As you can see mail1 and mail4 have much more accounts on them, but 
these mailboxes are much smaller.  Most of them are students.  Mail2 and 
mail5 are users with very big mailboxes.  In total we have 50947 
accounts on mail1-6, or about 1.2T of data.



I'm using 2.3.7 and eager to update, but will have to test that first.

Rudy

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Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
Directie ICT, afd. Infrastructuur  Direction ICT, Infrastructure dept.
Groep Systemen                     Systems group
Universiteit Gent                  Ghent University
Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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