Comments on: Unison - file synchronization tool

By: Feelmjawlk

Feelmjawlk — Sat, 26 Nov 2011 14:23:33 +0000

I would just like to report bad problems when using unison together with trickle. Large transfers tends to hang unexpectedly. I haven’t had problems with e.g. rsync and trickle, but it doesn’t seem to play nice with unison. Is anybody experiencing similar problems?

By: Bobjohn

Bobjohn — Sat, 23 Oct 2010 11:14:29 +0000

Do not use this tool - I may sound like a whiner - but I just lost 21Gb of data during it “syncing” a folder. It brought all the subfolders down off my remote drive bar one, which it decided to sync up to the remote drive, by removing all the files on the remote drive under that folder as they didn’t exist locally.

Thanks.

By: Bob/Paul

Bob/Paul — Sun, 04 Apr 2010 14:42:58 +0000

Chris: The description isn’t lacking, you just have to read all of it.

“Transfers of small updates to large files are optimized using a compression protocol similar to rsync.”

So, just like rsync, a few megs.

By: Chris

Chris — Fri, 19 Feb 2010 23:43:47 +0000

The description is lacking.

I’ve got a 50gig file in 2 places, one of them has had a few megs of mods made to it.

Is this program going to transfer a few megs, or 50 gigs, to bring the older file up-to-date?

By: gvanto

gvanto — Mon, 08 Feb 2010 06:55:39 +0000

I’d like to keep a synchronized folder on primarily my laptop (Windows XP), and my main desktop (Kubuntu Hardy heron - I like Hardy) and also (but less important), a desktop at work (with Win XP on it).

The main reason is to keep a synchronized version of a keepass db file (keepass is a great little app for storing passwords) but will be great to have it work for any files.

Keeping track of working copies thru SVN would be a great feature (I recently signed up for a VPS running kubuntu 8.10, to serve as a central svn repository).

If anyone has advice on what application (freeware preferably) that runs on Windows + Linux to achieve this, would be great to hear about it!

just curious if Unison would work for more than 2 machines and also if it is suitable for a central svn-repository setup?

Many thanks for help,
gvanto

By: Joe

Joe — Thu, 12 Nov 2009 16:35:36 +0000

Try http://code.google.com/p/git-sync/
It seems to do all this and much more (file versioning for example).

By: svrocket

svrocket — Sun, 10 May 2009 06:25:30 +0000

Hey I’m not trying to steal any thunder from Unison, if there is a significantly easier/better sync tool over ssh I’m all ears.

There is a mode to rsync, it takes 2 command lines where to update target to source and update source to target with a certain syntax and supposedly you get Unison-like behavior, Unforuntely I’ve never had the need to do *2-way* syncronization, I’m a “one-way replication” kind of guy where I make my shell scripts push new files from source to target, LEAVING the files on the target (do not delete).

Mostly I use Solaris and Opensolaris, which co-bundles or pre-installs rsync ver 2.6.9 so I’ve gotten real used to rsync. Also, I have to jump thru too many hurdles to add software that’s not pre-installed (lame feature of my workplace) so rsync wins by path of least resistance. But someday I’ll try Unison. And Dirvish. And ???

By: Anon

Anon — Wed, 08 Apr 2009 15:22:09 +0000

I prefer using my customized shell scripts with
rsync, scheduled timing, syncronize on logout, logs, report, and other neat stuff.

Insanely fast and fully automated.

Unison is uber slow and not totally reliable IMHO

Lol, the ubuntu screenshots watermarked are really sooo lame. screenshots from an open Source Operating system. lol, this cannot be un-seen.

By: andynu

andynu — Tue, 17 Feb 2009 08:08:34 +0000

For my bin directory, svn works great.

For my media (synced between work and home) unison is too slow. The hashing takes a full second per ~5m file; I’ve let it sit for days without completing the initial index. My wild unfounded accusation is that fastcheck doesn’t apply for the initial index, which is a shame since existence/mtime/date is plenty to differentiate the changesets I’m dealing with.

rsync on the other hand works insanely fast but doing:
rsync -auP a/ b/ rsync -auP b/ a/
while propagating additions well has the unfortunate side effect of resurrecting files deleted in either place.

By: alejandro

alejandro — Mon, 09 Feb 2009 13:19:07 +0000

Problem with perms?
To the file /home/.unison/[i]profile_name[/i] add string “[b]perms = 0[/i]“.
Enjoy!

By: Andy

Andy — Mon, 12 Jan 2009 09:20:25 +0000

@Svrocket as far as I can tell, there is no disadvantage to sticking with rsync, _as long as you only update one directory_. If you update both, like the example given above of adding new scripts to your bin directory on various hosts, unison allows this bidirectional capability.

I have not done any head-to-head performance testing, but I would be interested to see how rsync and unison compare on big directory structures with small changes, which is my most common use case.

Andy

By: linux-cloud

linux-cloud — Mon, 22 Dec 2008 16:57:27 +0000

Good write up. thankx

By: svrocket

svrocket — Tue, 02 Dec 2008 04:54:02 +0000

Long time rsync user here, primarily on Solaris. Can someone give me compelling reasons why I would discontinue using rsync for Unison?

rsync -avP source:/dir target:/dir

seems simple enough to me.

By: Roger

Roger — Mon, 01 Dec 2008 16:22:44 +0000

Unison doesn’t see my USB drive so I can’t sync any files there. Conduit is fine but gets an error 20% in to the synchronize, so I’m trying Unison as an alternative

By: Jan Lindh

Jan Lindh — Wed, 22 Oct 2008 19:16:27 +0000

Regarding unison and special characters like åäö:

Well this is slightly outside of ubuntu, but about half a year ago I set up my wifes windows PC to sync against my debian etch server. Using a minimum of cygwin with unison was the solution. Fixing so unison handled filenames with swedish characters wasn’t easy, but at last I found a way.

…problem is - I can’t remember how I did it!

The only thing that rings my mind is that this was a cygwin problem. And the fix could have been changing the Cygwin.bat file to:

-----------------Cygwin.bat beginning-------------
@echo off

chdir C:\cygwin\bin

set CYGWIN=tty

bash --login -i

-----------------Cygwin.bat end-------------

How the original looked like I can’t remember.

Not much of an answer, but at least something…

Good Luck!

By: Matt Canalegrande

Matt Canalegrande — Fri, 17 Oct 2008 10:38:17 +0000

I am simply stuck with
Received unexpected header from the server: expected "Unison 2.27\n" but received "Unison 2.13\n00000000", which differs at "Unison 2.1".
Server is ubuntu hardy 64
Linux ice 2.6.24-19-server #1 SMP Wed Aug 20 18:43:06 UTC 2008 x86_64 GNU/Linux
and client is hardy 32
Linux can 2.6.24-21-generic #1 SMP Mon Aug 25 17:32:09 UTC 2008 i686 GNU/Linux

How can I proceed to get these two synced?

By: stat

stat — Wed, 15 Oct 2008 14:38:30 +0000

I have played with unison but to me you are sacrificing a lot to have a gui interface. Rsync is your friend. I find it does the job faster, better and with less issues. The issue with unison about not working with differing builds drives me bats. I want a sync tool that is robust and just works. I don’t want to have to waste time trying to interpret why it might have failed. It is hard enough for me to have the discipline to do an actual sync.

By: KK

KK — Wed, 01 Oct 2008 10:21:38 +0000

Hi,

After sync, the copied file has the current date & time, is there any way or any other application can maintained the copied/synced file original modified date & time ?

thanks

By: mdlr

mdlr — Sun, 28 Sep 2008 09:44:33 +0000

It does take forever to hash large files. There are command line options like -fastcheck which look like they might help but they don’t appear to. I’m looking for a good way of syncing two directories with v large files in. All I want is filename and modified dates comparing. Any ideas?

By: mastapat11

mastapat11 — Sat, 12 Jul 2008 08:42:06 +0000

@Crazy:

Your suspicions of the hashing latency for large directories are justified.
i tried to sync two 400Gb+ folders and it took Unison 25hrs+ to complete the initial comparison and that doesn’t factor in the time to do the actual trans/changes!!! and the folders were 95% similar to begin with!

i was using it for a folder on Ubuntu client against folder on an ubuntu server over nfs.
the same thing using Synctoy on windows client against folder on ubuntu server over samba takes 5-10m.

i haven’t tried it again yet to see if it’s reduced and is just that long only for initial hash (too afraid).