[GLLUG] Samba as DC and netlogon.bat -> backup using unison . . .

Richard Houser rick at divinesymphony.net
Tue Nov 13 22:56:49 EST 2007

Hash: SHA1

Rsync was designed for efficient remote communication, so it doesn't
transfer all the data over the network for comparison purposes.
Saturating a local network is one thing, but if you are trying to do
something like a remote backup over the Internet, an algorithm like
described for unison can be very costly in terms of bandwidth.

For example, if you have a 4GB file and add 100K to the end, rsync
should only transfer roughly 100K of data for the update plus a little
more for the protocol overhead and differences detection.  The described
algorithm for unison would need to transfer all 4GB of data.

On the other hand, rsync does require code to run on both machines, so
it's not always an option with some of the less-friendly networks
(primarily semi-locked down Windows machines).

Nathan Hartley wrote:
> When unison compares files over a network share it does it no differently
> than it would locally, it reads the file in both locations from the hosting
> machine. In other words for unison to do it's magic the host machine has to
> read the data from the remote machine at network speeds. An alternative is
> running unison on both machines, one in server mode the other in client
> mode. Then, only the changes are transfered over the network. The unison
> documentation explains this far better than I could...
> http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-ma
> nual.html#remote
> Another time saver would be to note that by default Windows does not
> syncronize the 'Local Settings' folder, you could safely skip this as well.
> You may also find other folders and documents that could be skipped. 
> -ignore "/Local Settings/"
> -----Original Message-----
> From: linux-user-bounces at egr.msu.edu [mailto:linux-user-bounces at egr.msu.edu]
> On Behalf Of Benjamin Cathey
> Sent: Monday, November 12, 2007 9:56 AM
> To: linux-user at egr.msu.edu
> Subject: [GLLUG] Samba as DC and netlogon.bat -> backup using unison . . . 
> Okay - well, I got the command-line version of unison.  I am playing with
> the flags now.  It seems to take forever because it checks every file (some
> people have big "My Documents" folders).
> At the end it gives the nice little output that seems accurate about what
> has changed - I just wish it was faster -
> Going to try to turn the -fastcheck option to true and see what plays out -
> for now my options are:
> unison "%userprofile%\My Documents" x:\%username% -contactquietly -batch
> -prefer "%userprofile%\My Documents"
> --
> Okay adding -fastcheck true made it take 30 seconds for a 4.6 Gig folder
> instead of 4+ minutes.
> Cool.
> And it didn't seem to miss the changes I made.  So this is what I'll stick
> with
> Thanks again guys for all your help and suggestions.
> Benjamin Cathey
> System Administrator
> Cathey Company
> 4917 Tranter St.
> Lansing, MI 48910 USA
> Phone:     517.393.4720
> Fax:       517.393.4225
> Toll Free: 800.333.1972
> "Service is Our Profession"
> **********************
> **********************
> This E-mail message and any attachments may contain legally privileged,
> confidential or proprietary information. If you are not the intended
> recipient(s), or the employee or agent responsible for delivery of this
> message to the intended recipient(s), you are hereby notified that any
> dissemination, distribution or copying of this E-mail message is strictly
> prohibited. If you have received this message in error, please immediately
> notify the sender and delete this E-mail message from your computer. 
> _______________________________________________
> linux-user mailing list
> linux-user at egr.msu.edu
> http://mailman.egr.msu.edu/mailman/listinfo/linux-user
> _______________________________________________
> linux-user mailing list
> linux-user at egr.msu.edu
> http://mailman.egr.msu.edu/mailman/listinfo/linux-user

Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org


More information about the linux-user mailing list