On 19 Mar 2001 12:39:56 +0000, Barbara Greenwood wrote:
> Hi,
>
> I've recently joined a project supporting & developing a web-based email
> system which uses Cyrus (1.5.19) as the mail server. We currently have
> nearly 100,000 accounts (not all of them active) - Cyrus is rapidly becoming
> the bottleneck on the system. We would like to expand to support 500,000
> accounts, maybe even a million eventually.
i'm currently hosting ~400.000 accounts, 200.000 of them active (more or less)
on one sun 450 with 2 CPU's 1GByte RAM and FCAL adapter. The bottleneck are the
quota files, since they are stuffed in one directory. so there is a directory
with 200.000 files in it (luckily it's a veritas FS which does not degrade so bad
with big directorys as UFS does). We have a roundtrip time of 5 to max 10 seconds of
one 5MByte MIME email. (sendmail->Cyrus->IMAP client).
I'm currently working on a patch for 1.6.24 (will be ported to 2.0.x) to
stuff the quota files in the top level directories of the mailboxes.
This has also the advantage if there's a failover in our mailcluster, that the
quota files migrate automatically with the mailbox partitions to the backup server.
I plan to do some IMAP proxy hacking on perdition so that i can distribute the
mailbox across many servers. The currently implemented method in cyrus 2.x does
not satisfy me entirely, since i'd like to use LDAP as the storage method,
since we currently have LDAP with replication servers and load balancers in
production use and it's working perfectly.
i don't know nothing about Courier, since cyrus suites out needs just fine.
>
> Does anyone have any experience of supporting systems with these kinds of
> numbers? Is Cyrus appropriate for these volumes? How can we build in
> redundancy (i.e. keeping the system up even if the box goes down)?
>
> Also, some of my colleagues have suggested moving to Courier instead as they
> think this would give advantages in performance. However there would be a
> big hit involved while we migrated. Does anyone have hands-on knowledge of
> both Cyrus and Courier, and could offer any insight?
>
> Thanks,
> Barbara
>
