So, to follow up to my previous thread, we just successfully migrated our NFS-based mail cluster from qmail pop, courier imap, and bincimap to dovecot 1.1rc1.
Overall the transition was very smooth, the only unexpected adjustment was having to implement ntpd on each box, rather than doing an hourly ntpdate against our local ntpd server, to prevent dovecot from crashing itself from too much drift.
The impact has been severe! Even with NFS-stored indexes, our netapp is seeing 1/6th of the NFS ops per second, and its CPU utilization is now at 1/3rd previous levels.
The only user comment thus far was thanking us for bringing IMAP folders out from under INBOX.
Dovecot is truly excellent. In my book, Timo joins Wietse Venema and Marc Martinec to form the backbone of the premiere open source mail solution.
For now, praise will have to suffice. I do, however, maintain a little IOU list that I intend to fulfill at some point in the future, and Timo is now high on the list.
Thanks again! Andy