On Aug 4, 2008, at 5:46 PM, Sebastian Tymków wrote:

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No, but the problem has more to do with caching. If you use a
client that fetches the same data often (such as message headers/sizes) then
Dovecot will do the same work for each request. In that case in-memory
indexes perform poorly. This is more of a problem with webmail clients and
less of a problem with Outlook/Thunderbird.

And what about if I want use both solutions , memory indexing for POP3 and hd-indexing for webmail? Are there any disadventages ?

Well, assuming you're using Dovecot v1.1 it should already do most of
this automatically. It still writes dovecot.index and
dovecot.index.log files but it shouldn't touch dovecot.index.cache file.

But it probably wouldn't hurt to disable indexes for POP3.

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If you're using POP3 that also performs poorly without indexes with
v1.0. v1.1 makes it better.

Other problem is that indexes created on nfs sometimes get crushed
and I

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need to delete indexes in case of fetching mails ( I see mails on hd but when telnet on host and
make stat I don't see any).

So Dovecot says there are no mails while there are in fact?

Yes. But when I delete indexes and they are recreated everything
works fine.

Is it possible that something goes wrong on NFS connection ?

Instead of deleting indexes you could try if it helps to simply run
"touch cur new" in the maildir to make sure Dovecot resynchronizes the
mailboxes. If that doesn't help I'd like to get a copy of the
dovecot.index, dovecot.index.log and dovecot-uidlist files and "ls -l"
list of the files in new/ and cur/. (None of those files contain any
sensitive data).

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Does version 1.1.x correct this errors ? v1.1 makes NFS work a lot better, so it's highly recommended.

Does it stable version ? Can I use it on production without any
problems ?

Many people are.