cyrus and 500k to >1M mails per inbox

[Bron Gondwana]

On Thu, Feb 11, 2010 at 04:39:25PM +0100, Eric Luyten wrote:
> On Thu, February 11, 2010 4:23 pm, Carsten Hoeger wrote:
> 
> >
> > we have a customer running cyrus imap on RHEL5 cluster with a few thousand
> > mailboxes. Every single mail is sent to a second host acting as a read-only
> > archive (all imap acls set to no write access).
> >
> > The plan is, that all mail on that second host is kept for a long time.
> >
> >
> > After some years, old mail will be purged automatically.
> >
> >
> > It's quite likely, that these mailboxes will grow to 500000 or even more then
> >  1M mails per mailbox.
> >
> >
> > Does anybody have experience with such big mailboxes?
> 
> 
> Carsten,
> 
> No, I do not count more than 50k msgs in our largest mailboxes but I'd also
> welcome information on metadata (cyrus.index and cyrus.cache files) operations
> on huge mailboxes.
> Is the I/O cost of message adding relative to O(n), n being the number of msgs
> already in the mailbox, or is it independent thereof ?
> 
> (question hereby asked to the entire info-cyrus audience)

Stacks of stuff is O(n), sorry.  It's not really an ideal way to do things.
You'd be better off archiving per month for each mailbox and keeping the
messages counts to a reasonable number.

Bron ( it also makes purging 7 years ago or something a viable task )