This is an extension of my question here (Small office backups, small NAS (RAID) vs single disk).

What would be a good way to structure a NAS backup solution to prevent deliberate corruption by a person and\or malicious software.

Let's say I have a small office with 5-10 PCs. Sure I can have each PC mount the NAS and each user could have backup folders such as




I could use a script that runs on each PC at predefined intervals and copies the files appropriately. The issue with this is since the user can mount the NAS they (or malware running as their user) can potentially nuke all the backups for that User.

The only solutions to this dilema I can think of are:

  • Find a NAS that can poll the PCs via SSH (install sshd on them) and scp the files. I do not know of a NAS that can do this. I have been looking at QNAP turbo NAS.
  • Have a server poll the PCs via SSH and copy to the NAS (as only it can mount the NAS). This seems like a waste of a PC and inefficent.
  • Only have the user be able to access and\or mount the "daily" folder and have the NAS itself make copies to weekly\monthly\yearly at predefined intervals (Can a NAS do this)?
  • Some crazy software solution I never heard of?
  • Some NAS that runs a backup protocol I never heard of?

1 Answer 1


I think the simplest solution is just to have a different backup share for each user, so that they can only access their own backups and not anybody else's. This seems to solve your problem right there.

There are a number of backup tools that don't rely on being able to mount a remote filesystem, such as rdiff-backup, Amanda, Bacula, and probably others. This would solve your problem in another way, assuming you're able to to run the appropriate server on your NAS...

...which you are. Since a QNAP NAS (or similar home NAS) is typically just running Linux under the hood, you can technically have it do whatever you want...so if you want to run sshd on all your clients and have the backup server fetch files using ssh, sure, you can do that, but I think that's not an optimal solution.

  • I was not concerned with a user overwriting other people's backups as that can be solved with users\permissions or as you suggest mounting a different share. I was concerned with a user trashing all of their backups. For example if malware trashes User1's files as well as their daily, weekly, monthly, and yearly backups User 1 is screwed where as if they could not affect the weekly, monthly, and yearly backups User 1 can still be restored. Jul 26, 2013 at 17:51
  • In that case, any of the solutions that I mentioned that do not involve actually mounting a filesystem should work out great for you.
    – larsks
    Jul 26, 2013 at 17:54
  • Thanks. rdiff as I was looking at seems to use SSH so that means the user can still theoretically SSH into the host and trash their backups. I will look into them more. Thanks for the advice. Jul 26, 2013 at 17:55

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