Ever growing mailboxes and archiving

[Jeff]

On Mon, Apr 18, 2011 at 4:58 AM, Paolo Cravero <pcravero at as2594.net> wrote:
> Good morning.
> I am looking for a server-side archiving solution to be applied to a
> relatively large cyrus installation.
>
> The customer eats up ca 4 TB of data over about 4000 accounts. No quota.
>
> The competition is: who will die first? The web-based client or our
> SAN+backup system? :-)
>
> I am aware cyrus can handle the folder tree of a single account over
> different cyrus partitions. This might mean more complex maintenance and
> way longer restore times but it does indeed require 100% good user
> behavior in archiving old messages in the proper subtree. Unless
> administratively old messages are moved away once a year (what an impact
> on I/O and backups...).
>
> A good search engine did not return useful links, or I used wrong keywords.
>
> Some commercial email products have solutions to handle old messages or
> just their attachments: is there something that would apply to our
> beloved cyrus?
>
> How do you handle large and rarely accessed old messages?

I have not yet attempted to implement this, but I have looked at
dovecot 2.x with dbox mail store format. A new feature allows an
alternate storage location based on criteria you choose, in this case,
message age. See http://wiki2.dovecot.org/MailboxFormat/dbox, scroll
down to the last section "Alternate Storage". In theory, you could do
a single backup of the alt-storage location after you do a "doveadm
altmove" and then, unless mail arrives with bogus dates, nothing new
would go there and you need not back it up until your next manual
adjustment to the cutoff date.

Please don't hate me for mentioning dovecot on this list, but as far
as I can tell, cyrus has no such storage feature. Am I excited about
changing mail servers? Heck no. Am I going to do it anyway? Maybe...
But my installation is orders of magnitude smaller than yours, so I
can better afford the risk.

I will repeat: I have not tested this feature. I mention it based on
advertised capability alone, not on actual experience.

That said, I will be eagerly monitoring this thread for a pure cyrus
solution to the problem.
--
Jeff