Quoting Rick Romero rick@havokmon.com:
See that last line there??? Want to bet something in the mail setup (MTA, dovecot, system jobs like backup, etc) put an exclusive lock on files from time to time?
I thought the entire reason (ok not the _entire_ reason but..) for
Maildir was to avoid locks and allow easy concurrent access to a
mailbox through many different applications.
Okay, so if you are real careful (use maildir instead of some other format like mbox, don't use it for your dovecot index/control files, don't do native backups but use a snapshot, don't involve any other programs which might introduce locks, etc. then you can probably get away with it. But I still wouldn't bet on it.
So while I do agree that file locking is a possible problem in an
active/active setup with FRP, I think it's possible - as long as the
admin is aware of the risks.
And the ways to avoid locking... And assuming locking is the only issue (other issues may arise depending on implementation).
Yes, there are definitely things to be aware of. I'm not sure if
this is the place to hash it out, but I think that while it's not a
cheap solution it may fit MY environment - and possibly others who
use Maildir.
OP didn't specify many details, so assumptions were made... On my system, I share mbox files and dovecot indexes, and they both having locking...
I guess everyone is as cheap as I am and hasn't set it up yet :)
Uhm, DRBD is free and this suggested alternative isn't AFAIK, so I don't think it is being cheap... I'm thinking it is more about reputation and install bases...
Rick
-- Eric Rostetter The Department of Physics The University of Texas at Austin
Go Longhorns!