On 5.3.2012, at 19.25, Jacek Osiecki wrote:
However, if we have everything redundant, why not have the same with SMTP and POP3/IMAP? But - won't anything fail if two (or more) dovecots are accessing the same disk space, both for IMAP/POP3 and LDA/LMTP?
If both servers randomly access users' mails, with NFS you'll have some trouble, with OCFS2 probably less trouble. But in both cases you'll have better performance and no problems if you use Dovecot director in both servers (install both director and backend to both servers). http://wiki2.dovecot.org/Director
Thanks, I'll probably give it a try. On the other hand, it would be nice to have a possibility to allow multiple dovecot instances to access mail spool (at cost of handling some extra file/directory locks) - a bit slower, but safe...
You can safely do that with director.
Also the problem with NFS isn't locks, but caching.
Another question: as I assume, when you wrote about troubles it was applying to IMAP. How about LMTP/LDA? Can anything bad happen when one mailbox is being filled by LMTP/LDA from more than one server)?
Yes, because they're still updating Dovecot index files. You could disable LMTP/LDA index updates, but I'm still not sure if it works 100% correctly (because dovecot-uidlist is appended to).