Marten Lehmann wrote:
Dovecot is really fine, but it still isn't NFS ready. Especially when using dovecot as pop3 only this index-stuff must be disengageable. What is the use of generating a complex index file for hundreds of messages, that will be deleted in the next step after downloading them?
Well, part of the issue is that Dovecot is _primarily_ an IMAP server, where these indexes prove invaluable to its performance. The POP3 side is more of an added bonus.
But the index is also a problem when using IMAP over NFS.
This is why you can configure Dovecot to use indexes on the local disk, or in memory, as I believe someone else has already mentioned.
Access to the files is too slow, so the connections keep hanging around and the i/o waiting value is raised to a maximum which slows down the whole machine. It simply doesn't make sense to build and update an index every time the maildir is accessed (which is very cpu and timeconsuming), while search operations (the only moment when the index is actually used and not just heavily updated) don't affect even 1% of all IMAP calls (and such a command doesn't even exist for pop3).
I was fairly sure Timo has the index doing more than what you'd at first expect.
I would be much obliged if you could create an option called "--disable-index" in the configure-script or something like "disable-index = yes" in dovecot.conf that makes dovecot ignoring existing index files and doesn't care for related operations, so NFS should work much faster and IMAP search would simply parse the files directly instead of looking in the index.
All that being said, I do agree that this option could well have its place. I suspect Timo might even say it's possible to have a "no-index" plug-in to handle this.
-- Curtis Maloney cmaloney@cardgate.net