On 29.3.2012, at 2.51, Jeff Gustafson wrote: >> Most of the time is spent on usermode CPU code. I doubt the problem is dsync >> itself, most likely the problem is mdbox's saving code. Or possibly >> index/cache code. Try the same dsync backup for: >> >> - mbox:/tmp/mbox >> - mbox:/tmp/mbox:INDEX=MEMORY >> - sdbox:/tmp/sdbox > > My tests show that maildir to mdbox or sdbox backup/conversions take > about the same length in time. I noticed maybe a second or two > difference between mdbox and sdbox). On a 3.1GB mailbox either one took > about 6 minutes. Rsync, on the other hand, took less than a minute. I > will re-run the tests with a maildir to maildir backup and see how long > it takes.
Try also with INDEX=MEMORY, since the problem may be related to updating the indexes. Another way to test if the problem is dsync or Dovecot's generic mail saving code is to run: time doveadm -o mail=mdbox:/tmp/mdbox import mdbox:/path/to/real/mdbox "" all Or if it's the mail reading code: time doveadm fetch -u user@domain text all > /dev/null
