[Dovecot] Dovecot vs Exim file locking

[Daniel Campos]

Hi all:

We're planning to deploy a large e-mail system storing maildirs in a NAS
system through NFS. One of the options we're thinking on is using
Dovecot+EXIM.

As far as I've read in both project's documentation, both services implement
locking allowing multiple servers to access the same maildirs in order to
distribute the service load. However, I can't find any information
explaining whether both locking mechanisms are compatible, whether any
additional configuration is needed both in Dovecot and/or EXIM, or even
whether any locking synchronization between both services is
needed/recommendable at all.

The only remote clue I've found is that, according to Dovecot docs: "Because
Dovecot uses its own non-standard locking (dovecot-uidlist.lock dotlock
file), other MUAs accessing the maildir don't support it." (but EXIM is not
a MUA, anyway)

Anyhow theoretically MailDir could even be considered free of locking
problems, but I'm not sure of the real implications of putting together
several Exim and Dovecot installations pointing to the same NFS filesystem. 

Any knowledge/experience/link/clue on this would be greatly appreciated.

Thanks in advance,

Daniel Campos