On Tue, 31 Jul 2007, Marc Silver wrote:
>
> However, shared disk isn't an option in my current environment, so I was
> hoping some of the guru's here had some suggestions as to how I could
> have a mail replicate across multiple servers (like powermail can do,
> but supporting IMAP), taking into account that both IMAP servers would
> actively be servicing clients (ie, active-active).
http://www-uxsup.csx.cam.ac.uk/~fanf2/hermes/doc/talks/2004-02-ukuug/
The replication code that my colleague David Carter wrote for Cyrus is
included in version 2.3, and is used by Fastmail as well as Cambridge -
and possibly other sites I don't know about.
It is master-slave only, so you can't point clients at the replica without
failing over to it. We divide our message store into pairs of live and hot
spare machines, which keeps system management simple. The Fastmail guys
sub-divide their servers into chunks with an independent IMAP server for
each chunk, so that a server can have a mixture of live and spare chunks.
This also helps to reduce filesystem sizes and therefore fsck time. We
found that ext3fs could cope with a 3TB filesystem admirably.
Tony.
--
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