On Sat, 2012-03-24 at 14:21 +0100, 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 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?
The destination directory was empty. I was doing a full backup. > dsync does so much more than simply copy some files... I realize that. I am hoping that the extra data that dsync has available to it would improve the speed of syncing backups. My baseline testing of simply backing up a mailbox to an empty directory shows that dsync is takes way too long to backup a single mailbox. I have over a terabyte of data to backup. I'm currently using rsync and it must traverse tens of thousands of files and check the time information. It works, but I was hoping dsync would be a better solution. dsync should be able to sync faster, by gulping in the index information for each mailbox. I haven't even moved to the point of sync'ing since the baseline test of simply exporting a mailbox is so slow. ...Jeff