Mail Archives: cygwin/2004/07/13/06:56:18
Hello all,
Thanks for the help so far, on this issue with the mysterious
non-network based rsync slowdown. To recap...
Brian Dessent wrote:
> Reini Urban wrote:
>> Alexis Gallagher wrote:
>>> When the file is alredy there, rsync reports a speedup of about
>>> 70. (When the file is not already there, the speed up is 1, of
>>> course.) I am running rsync over ssh with pre-generated keys
>>> installed in my .ssh directories.
>>
>> This is a binary MP3. rsync (as diff) is not good in checking
>> binary diffs. Please try it with a typical text file, where the
>> patch is smaller than the source.
>
>
> That is not correct at all, and rsync would be much less useful if it
> were true. rsync works with arbitrary binary data just as well as
> it does with text.
In any event I checked Reini's theory using a 5 MB text file that
consists only of x's and newlines. So unlike an MP3, this file is
non-binary and extremely compressible. And what I observed was as follows:
scp: 348800 bytes/sec
rsync (file not there): 303075 bytes/sec, with speedup of 1
rsync (file already there): 733 bytes/sec, with speedup of 70
This is pretty much exactly the same problem as I was having with the
MP3 file. And I'm still quite puzzled.
Cheers,
Alexis
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