On Mon, 2007-04-16 at 10:41 -0400, Justin McAleer wrote:
Ok, I'll give more detail about the setup. I plan to use the convert plugin to migrate from CommuniGate to dovecot for our ~160,000 accounts. We will probably migrate one domain at a time, letting users basically migrate their mail at first login. But, we will also go through all the domain's accounts logging in to pop3 just to ensure everything gets moved.
OK, that also causes it to read the mailboxes and save the message sizes to cache files.
So, for testing, I've copied a few of our domains' mail spools over to the test server and started a script that forks and goes through all their accounts and simply logs in to pop3 and waits for a message list to come back. We have the maildirs being stored on an NFS mount though, and indexes on localdisk, so the only localdisk activity was logging and indexes.
And reading the mail spools? :)
I'll try setting both of those options and see how much difference it makes, although I'm not sure that losing mail upon server reset is acceptible for us (disabling fsync).
It could be done pretty easily only for index files by modifying the sources. I guess another option should be added for this.
Anyway, Timo and others, do you have any thoughts about keeping indexes on a tmpfs partition? I realize the obvious issues with this: running out of space, and the fact that the partition is lost on reboot.
I think memory would be better used for keeping mailbox data cached that's actually useful at the time.
Perhaps, but one way or another, we apparently cannot use a simple localdisk for indexes. So, the options are either memory or some sort of raid setup. Since we use maildirs, isn't the disk cache aspect less of a concern?
Depends on how mailboxes are accessed. If message contents are read only once then I guess it doesn't matter. Probably the worst offender here is SEARCH TEXT/BODY command.