I wish to create an off-site backup for my critical files and I'm looking for suggestions. 

I've read a few posts (http://forum.openwrt.org/viewtopic.php?pid=50682) about this topic but am not aware of what backup programs/methods are available for OpenWRT.  What options are there?

I already have two WRTSL54GS units, one of which is working well as an OpenVPN server and router for my LAN, the other of which will be off-site with a 320 GB hard drive attached to it.  I wish for the remote WRTSL54GS to open a VPN connection to my LAN and grab a prepared/compressed differential backup file from a Windows XP file server and a Linux webserver.

At the end of the week, I want another nightly "differential" backup to occur but this time, I want all of the differential backups from the week to be combined, in sequential order, with whatever "full-backup" copy is in the drive, thus creating a new "full-backup" of the file server.  I haven't decided how I want files to be deleted off of the off-site backup drive (yet) although I think I will have them be moved to a "deleted files" directory and stored there until I manually delete them or a specified period of time has passed (like a month or something).

Finally, I'm not sure if leaving the remote hard drive running all of the time is required.  Is there any way to put a disk to sleep and then wake it up when needed (I've read about this too and seem to think the answer is "no," but perhaps someone knows better)?

Some of these tasks could be easily accomplished by CRON, wget, and SAMBA (client) but I'm sure someone has some good ideas on how I could do this.  Any input would be greatly appreciated.

I built something similar to what you may be looking to do.

I grabbed DeltaCopy for the windows boxes, and installed its rsync via the happy GUI install.  I found Samba to be implemented so poorly under windows that it was all but unusable.

I found the BOBS backup app, which uses rsync and link rotation to back up a remote machine in a manner that is so confusing, that I will be using rDesktop very soon.

I don't think that the little openwrt boxes - especially not the linsys WRT54GL units - will have enough mem space to hold the rsync differential comparisons.  Please tell me if they do, because I bailed out and grabbed a 4 year old machine for a linux backup and storage box.

I think that rDesktop gets you most of the way there, and the wall we all bump up against is really windows.

Finally, HDDs sleep.  Then they wake up.  It's no big deal.

What does rdesktop have to do with backups?  I think you must mean something else

I agree that the RAM will likely be a problem.  Maybe you can get the router to swap to the disk, but that might not be a good idea either.

Just downloading pre-compressed tarballs (or whatever) as mentioned by bkloppenborg should be fine.  For the "full backup" bit, do you (bkloppenborg) mean that you want to take a full backup from a previous run and then update it with each "differential" backup in sequence to get to the new full backup?  That should not be too difficult.  You will probably have to include a list of files to delete in the differential backup.

Wodin,

You are correct.  I wish to apply the "differential" backups, in sequence, to an existing "full backup" to create a new full backup.  It is clear that RAM will be a problem with using rsync, however after the first synchronization there shouldn't be too many changes (i.e. maybe 100 files per day, not thousands of files).  Perhaps I should order an additional RAM chip and add it to the router, give it 64 MB of RAM, before I place it in it's new home.

Why wouldn't swapping to disk be a good idea?  Hard drives can handle it although the swap process would be slower.  I guess if the disk were offline or somehow disabled, there would be some problems.  Can the swap space be dynamically moved without rebooting?  Perhaps, if that were possible, I could move the swap space over to the drive during the backup, and then move it back to RAM after the backup is completed.

Let me know if you have any other ideas.  These are good suggestions thus far.

It looks like someone has already posted something similar to what I need to the wiki:
http://wiki.openwrt.org/rsync-usb-sambaHowTo, although it appears that they have the client rsync to the backup device.  Of course, I would like to do it the other way around (have the backup device initiate the sync, grab the files, and store them locally).  So, there are a few more good ideas, such as emailing the results of the sync.

(Last edited by bkloppenborg on 3 Feb 2008, 19:26)

I've updated my router to Kamikaze and have completed my offsite backup solution.  This information is posted in the Kamikaze form on this thread.

Here is a simple service that offers RSYNC, SFTP or SCP.  You can use any client that supports those protocols.

And it's only 2.99 a month for unlimited storage.

www.datastorageunit.com

(Last edited by jwooton on 7 Dec 2009, 19:01)