Optimizing Performance with big mailboxes

[dzlabing]

Hi,
I am running roundcube 0.3 on a Debian machine, Webserver Apache 2.2.9,  Courier IMAPD (using MailDir) , postfix on an AMD XP 2k 1,6 GHz, 1GB RAM.
I switched form Squirrelmail to roundcube which had no problem with 2000-7000 mails per IMAP-folder.
Now when I access a specific folder I have to wait:
Inbox 2832 mails: 3s
Spam 4147 mails: 28s

As the basic setup had no major performance problem when running with Squirrelmail I am asking if there is a specific option in the configuration of roundcube which has a major impact on performance or if there would be some additional configuration which could increase performance (eg. IMAP proxy).

Having said this: roundcube is great.

Thank you.

Dietmar

PS: I am new to this forum, I hope I did not miss a similar thread.

[rosali]

Does your IMAP server support "IMAP SORT"? If not, RoundCube has to fetch date headers from all messages in a box. RoundCube is really fast when the server supports "SORT". For detailed informations follow the mailing list here: RoundCube Mailing Lists

[dzlabing]

Thanks for the reply and the link. The discussion on the mailing list basicly suggests to enable caching (it is enabled), use dovecot (I have to check how it fits into my installation).
top shows that for some seconds mysqld eats up CPU  power (probably trying the cache) and then IMAPD is on top for several seconds. It seems that caching somehow fails (possibly because there was some change in the message list or the size of the cache is too limited).

IMAP seems to support SORT, see the welcome string below:

Dietmar

telnet localhost imap
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2008 Double Precision, Inc.  See COPYING for distribution information.