On 5.4.2011, at 16.59, Reinhard Vicinus wrote:
i'm in the process of evaluating dovecot. I have a rather big testing environment with four dovecot director frontend instances and four dovecot backend instances. Mailboxes are all in mdbox format and stored on nfs. Indexes are stored locally.
With mdbox you must not lose indexes! They contain very important information that doesn't exist elsewhere, like what mailboxes mails exist in and what flags they have. You really need to keep index files on NFS too.
dovecot nfs setup for high performance is used (mmap_disable = no, dotlock_use_excl = yes, mail_nfs_storage = yes, mail_nfs_index = no).
With director you can keep mail_nfs_*=no. Also note that to deliver mails you need to use LMTP via directors.