On 24/03/2012 13:21, Maarten Bezemer wrote:
On Fri, 23 Mar 2012, Jeff Gustafson wrote:
That didn't seem to make much of a difference. On a 3.1GB backup itshaved 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.
rsync is only going to transfer files it believes has changed, so the transfer bandwidth will likely be lower
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?
Dovecot is not very resiliant to files changing under it, but without the filename changing. I have no idea if it's supposed to work at all, but you might at least expect to see problems if you start doing this?
dsync does so much more than simply copy some files...
Quite probably, but I don't think your expose above illustrates this?
Regards
Ed W