Dear Timo,
Would there be any sense in giving Dovecot the option to split folders into multiple subfolders when they reached a specified size (probably message count) limit?
Dovecot would monitor folders and when they reached, say, 10,000 messages, silently split the folder on the filesystem to ensure that access remains fast.
I know that Dovecot scales very well but this would give practically unlimited storage capability and also keep things fast. You could even have it so that the latest 100 messages are kept in their own folder for fast access.
.Folder.new .Folder.cur .Folder.tmp
could become:
.Folder__1.new .Folder__1.cur .Folder__1.tmp and .Folder__2.new .Folder__2.cur .Folder__2.tmp
with Dovecot merging them before display as just "Folder" within the mail client.
This could be further extended so that Dovecot could be configured to store 'old' message folders in a separate location. We could then have slower+cheaper+larger storage mounted so that 'old mail' does not take up the expensive local SCSI disks on the machine. Mail from 2 years ago is much less likely to be accessed than mail from the last week.
This would provide very neat behind-the-scenes archiving functionality.
Looking forward to hearing your thoughts.
Best, Daniel
-- Squirrelmail Stable 1.4.8 (and developing on 1.5.2) PHP 5.x Hardened with Eaccelerator Apache 2.x Mysql 5.0.x Imapproxy over Dovecot 1.0.rc27 with Maildir all running on Gentoo Linux for ~5,000 users.