[Dovecot] new configure-option --disable-index
lehmann at cnm.de
Fri Jan 13 19:04:15 EET 2006
I experimented with dovecot the whole evening yesterday and the
mailserver worked fine since there haven't been that much users
connecting to it. I'm using dovecot 1.0.alpha5 as pop3 and pop3s server.
The maildirs are mounted through NFS and since there is no nfslockd
running I disabled mmap in the config and told dovecot to use dotlock.
Also I experienced, that dovecot was much faster when using one
login-process per connection instead of sharing them throughout several
connections. Sharings seems to be a greater performance problem
(bottleneck) than additional fork()s.
However, under normal load at business time the server load increased to
a value that made it impossible to download emails without timeouts, so
we switched back to tcpserver/qmail-pop3d for pop3 and only kept dovecot
for doing the pop3s part.
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? But the
index is also a problem when using IMAP over NFS. 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 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.
I would really appriciate this very much and I'm absolutely sure, that a
lot of people beside me are waiting for this.
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