This is the mail archive of the cygwin mailing list for the Cygwin project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

RE: rsync under cygwin too slow


Its because that's not how rsync should be used over the network.

There should be a copy of rsync running on the remote machine that reads the remote files and sends only the checksums.

The setup shown here (as guessed) has the loca rsync read the remote files over the lan in order to get the checksums.

Disabling checksums and using timestamps can help but is much less certain.

Better to use rsyncover ssh.
Sam



-----Original Message-----
From: KHMan <keinhong@gmail.com>
Sent: Tuesday, March 24, 2009 3:16 AM
To: cygwin@cygwin.com
Subject: Re: rsync under cygwin too slow


Alfred von Campe wrote:
>> rsync -rtuplg --stats --verbose --progress --modify-window=2 
>> /cygdrive/c/localfolder /cygdrive/z/backups/
>> ...
>> ...
>> The local and remote folders were already synchronized, that is why 0 
>> files were transferred. File list generation did take only 3 minutes 
>> but the whole process took more than 1.5 hours to finish and consumed 
>> a whopping 1.9 GB of downloaded bytes and 0.4 GB of uploaded bytes as 
>> per network counters. For what? Zero files, Zero bytes of file data.
> 
> I'm pretty sure this is because rsync has to copy all the files locally 
> to compare them to see if they need to be copied.  Try running the rsync 
> as a service on the system that hosts the Z: drive (or run rsync over 
> ssh to the system that hosts the Z drive) and you will see large 
> performance improvement.

Looks to me there is no --checksum option, so rsync skips based on 
size and modtime. I do something similar to Vinod. Here is an 
extra data point to compare against (y and u are on separate 
drives on same machine):

$ time rsync -a --progress --stats --delete /cygdrive/y/Installs/ 
/cygdrive/u/Installs/
sending incremental file list

Number of files: 284
Number of files transferred: 0
Total file size: 2284961277 bytes
Total transferred file size: 0 bytes
Literal data: 0 bytes
Matched data: 0 bytes
File list size: 8583
File list generation time: 0.030 seconds
File list transfer time: 0.000 seconds
Total bytes sent: 8606
Total bytes received: 22

sent 8606 bytes  received 22 bytes  17256.00 bytes/sec
total size is 2284961277  speedup is 264830.93

real    0m0.678s
user    0m0.155s
sys     0m0.217s

With --checksum:

$ time rsync -ac --progress --stats --delete /cygdrive/y/Installs/ 
/cygdrive/u/Installs/
sending incremental file list

Number of files: 284
Number of files transferred: 0
Total file size: 2284961277 bytes
Total transferred file size: 0 bytes
Literal data: 0 bytes
Matched data: 0 bytes
File list size: 12951
File list 

[The entire original message is not included]

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]