[Dovecot] Hints for a NFS-Setup

[Patrick Westenberg]

Hi everyone,

as I have often trouble with OCFS2 I want to switch to NFS but
I'm not sure how to rebuild my cluster with regard to locking
and indexing problems.

By now my I have a four server configuration (there are another 2
servers for outgoing mail but they can be ignored):

MTA(MX10) --(lmtp/socket)--> local dovecot --> iSCSI-LUN with OCFS2
MTA(MX10) --(lmtp/socket)--> local dovecot --> iSCSI-LUN with OCFS2
IMAP-User <--(imap)--> IMAP-Server1 (local dovecot) <--> iSCSI-LUN/OCFS2
IMAP-User <--(imap)--> IMAP-Server2 (local dovecot) <--> iSCSI-LUN/OCFS2

As far as I understood I will get poor performance if I'd just switch
from OCFS2 to NFS (while keeping this configuration) with 4 hosts
accessing the NFS-share and the index files on it and it is recommended
to assign users to a specific host (http://wiki2.dovecot.org/NFS).

I'm uncertain what's the meaning of "user" in this context. Is it an
IMAP-User or every incoming mail?

An IMAP-User assigned to a specific IMAP-Server is ok for me and I
could store and profit from local index files. However, I want my
incoming mailservers to be equally receiving mails. Both should accept
mails for every mailbox but in this case I won't have local indexes.

I would appreciate any hints.

Patrick