We are currently running imap-2002.RC8 on a Linux box with ext3 FS
We are intending to upgrade the system and I was trying to benchmark various filesystems, IMAP servers and mailbox formats to see whether, for instance, there was benefit moving to XFS or Reiser. I built imap-2006.DEV.SNAP-0606151542 under SL4 (~= RHEL3) on a text system, and enabled the filesystem support as-shipped. I found the Netscape Mailstone project, now under Mozilla, which I was using as a benchmark. It sets up multiple threads on multiple clients and can user various protocols. What I was doing was to load up 100 inboxes with SMTP, then use IMAP to retrieve the messages, using the standard templates. http://www.mozilla.org/projects/mstone/ I was quite surprised to see that the Unix mailbox format outperformed the MBX format by a factor of 2. I had always taken it on faith that MBX would outperform Unix, from the documentation and an understanding of the format - being able to set message flags without inserting characters, and being able to seek through the file using the linked list seemed naturally more efficient. mbx xfs - 5 Mbytes/s http://andrew.triumf.ca/mailstone/20060623.1610/results.html unix xfs - 11 Mbytes/s http://andrew.triumf.ca/mailstone/20060626.1934/results.html mx xfs - 400 Kbytes/s http://andrew.triumf.ca/mailstone/20060627.1030/results.html Comments ? I am intending to benchmark the Dovecot IMAP server that comes with SL4 Linux, and also cyrus-imapd, but have not yet done so. Understanding the various possible inbox formats to get mail delivered onto the user partitions instead of the spool takes me a while ... I note that the Dovecot documentation recommends Maildir format (like MH or MX ?) over Unix format for anything except read-only mail, on the grounds of robustness, saying that the performance is OK with a tree-structured filesystem such as XFS or Reiser. I notice that the UW MX format indeed has better performance under XFS, but is still not "OK". In Reiser 3, it is no better than ext3. I have not tried building Reiser 4, still marked "experimental", which others say has the best performance. Some here have complained about the MBX format (or Unix, for that matter) saying that it makes the system hard to back up. Our backup systems (Amanda, Dirvish, rsync..) have no ability to use incremental or differential backup on individual files, and every mailbox that received any messages or had any flags changed must be copied in its entirety. Which takes a while, what with these hundred-megabyte inboxes people have. -- Andrew Daviel, TRIUMF, Canada Tel. +1 (604) 222-7376 (Pacific Time) [EMAIL PROTECTED] _______________________________________________ Imap-uw mailing list Imap-uw@u.washington.edu https://mailman1.u.washington.edu/mailman/listinfo/imap-uw
