[Bug 8512] New: rsync -a slower than cp -a

samba-bugs at samba.org samba-bugs at samba.org
Fri Oct 7 08:23:36 MDT 2011


https://bugzilla.samba.org/show_bug.cgi?id=8512

           Summary: rsync -a slower than cp -a
           Product: rsync
           Version: 3.1.0
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P5
         Component: core
        AssignedTo: wayned at samba.org
        ReportedBy: linux.news at bucksch.org
         QAContact: rsync-qa at samba.org


Reproduction:
1. du /foo/bigfile
2. echo 3 > /proc/sys/vm/drop_caches
3. time rsync -avp /foo/bigfile /bar/bigfile
4. echo 3 > /proc/sys/vm/drop_caches
5. time cp -a /foo/bigfile /bar/bigfile

Actual result:
1. ~1286 MB
3. 27.9s, 45.9 MB/s per calc, 45.61 MB/s according to rsync
5. 14.6s, 88.1 MB/s per calc

In other words, cp is *almost twice as fast* as rsync. On a single big file
where no comparison is necessary.

Expected result:
When copying a file, rsync is as fast as cp.

rsync is great, but this is a real putoff. I don't see a good reason either, as
the two programs perform the same function in this case. Must be some design
problem. Find the bottleneck and eliminate it, please.

Importance:
rsync advertizes with its speed.

-- 
Configure bugmail: https://bugzilla.samba.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.


More information about the rsync mailing list