[Dovecot] dsync is SLOW compared to rsync

[Maarten Bezemer]

On Fri, 23 Mar 2012, Jeff Gustafson wrote:

> 	That didn't seem to make much of a difference. On a 3.1GB backup it
> shaved off 5 seconds. dsync's time was over 6 minutes with or without
> the mail_fsync=never. rsync copied the same 3.1GB mailbox in 15 seconds.
> 	It seems to me that dsync *should* be able to be just as fast, but it
> currently is spending way too much time doing something. What is it?

Syncing 3.1GB in 15 seconds would require a speed of more than 200MB per 
second. Depending on the harddisks used, that would be quite a challenge. 
If you use rsync to only transfer the files that changed (based on file 
modification time) you may or may not miss files that have changed but 
still have the same time stamp. I assume you didn't use the --checksum 
parameter to rsync, right?

dsync does so much more than simply copy some files...

-- 
Maarten