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
On Sex, 18 Dez 2009, Daniel Campos wrote:> 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.As far as I know, maildir does not require locking. I used sometime exim + dovecot without problems. Now I use dovecot's deliver, by doing that you'll certainly have no problems. -- Genius doesn't work on an assembly line basis. You can't simply say, "Today I will be brilliant." -- Kirk, "The Ultimate Computer", stardate 4731.3 Eduardo M KALINOWSKI eduardo at kalinowski.com.br
On Dec 18, 2009, at 8:41 AM, Daniel Campos wrote:> 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.Mail deliveries don't require any locks with maildir. But for Dovecot, be sure to read http://wiki.dovecot.org/NFS