[Bug 12498] New: --fuzzy --fuzzy hugely impacts performance even if its' not needed

samba-bugs at samba.org samba-bugs at samba.org
Thu Jan 5 15:29:02 UTC 2017


            Bug ID: 12498
           Summary: --fuzzy --fuzzy hugely impacts performance even if
                    its' not needed
           Product: rsync
           Version: 3.1.2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P5
         Component: core
          Assignee: wayned at samba.org
          Reporter: ben.rubson at gmail.com
        QA Contact: rsync-qa at samba.org


I make backups to a Rsync daemon.
Each backup is made to an empty directory, using 20 --link-dest parameters, so
that already uploaded files are hard-linked.

I made some tests adding --fuzzy --fuzzy so that non-existing files can use a
base-file, when possible.

It works perfectly, really good thing to find a base-file within link-dest

However, it really slows down the backup process, even when it's not needed.
For example, it terribly impacts performance even for a backup with no new
files at all, for which all files will be hard-linked.

Here are some backup durations for a backup with no new files :
- without -yy                 :  9 seconds
- with -y                     :  9 seconds
- with --y and  1 --link-dest : 11 seconds
- with --y and  8 --link-dest : 22 seconds
- with --y and 20 --link-dest : 37 seconds

My question is then, could it be possible for --fuzzy --fuzzy (-yy) to only
work for files which really need to be uploaded ?
So to avoid working for files which will simply be hard-linked.

Would such a modification only impact daemon side ? (would be great)

Thank you very much !

Best regards,


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