Steve Bertrand wrote: > What I don't have, and have always wondered about, is live redundancy > for the IMAP/POP services. > > I know that this would be a challenge to some degree considering the > high volume of data changes. > > Perhaps a carp(4) setup between a couple of MDA's, where when the > primary is up, a constant rsync pushes the data to the backup. Or > perhaps a combination of rsync for manual changes, and a method to have > the primary write the emails to a local disk, and a network disk > simultaneously? > > If anyone has a setup that has redundancy for their IMAP/POP services, > and a method to keep the changing data relatively up-to-date, I'd love > to hear about it.
Now, that is a different kettle of fish. This is a job for cyrus imap. I suggest googling for 'cyrus murder' -- this is almost, but not quite, a fully resilient mail store / IMAP system. Your mail store is divided into frontend IMAP protocol servers which handle user auth etc. and back-end mail stores. The protocol layer servers are fully resilient and you can fail over a user session at will, but the mailstores don't quite get there: mail is replicated across different stores, but actions modifying the mail store are not transactional across all the mail stores. Or in other words, you can lose a small amount of data if one of the mail stores goes bang at precisely the wrong moment. Even so, it will do better at keeping multiple copies of a mailstore in synch than any locally scripted rsync setup. Cheers, Matthew -- Dr Matthew J Seaman MA, D.Phil. Flat 3 7 Priory Courtyard PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW, UK
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