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jonny
Asked: 2011-09-22 08:37:15 +0800 CST

How To Prevent Access To Unmounted Mount Point

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Ok, I have this in fstab

  //windows_mashine/Backup /backups cifs credentials=/root/.credentials,rw,_netdev,iocharset=utf8,uid=1000 0 0

I have rsnapshot in my cron which backups /etc/ and /usr/local/ and some other files to /backups

Recently I find that when other mashine is down and /backups cannot be mounted rsnapshot backups to physical folder /backups thus it eats partition / space. How can I avoid this?

Can I prevent any writing to /backups when it is not mounted (rsnapshot runs as root, since it need to backup some system files)

backup mount rsnapshot

3 Answers

  1. Best Answer

    Another option is to set the directory to be immutable. To do this you need to run the following command with the mount point unmounted.

    chattr +i /backups

    I do this on any directory that is intended to only be a mount point just to prevent this sort of thing. Because there are situations where you're not in a position to add a check to see if something is mounted. Like if the process isn't a script that you control or it's a human that is generating or moving the data. This approach will prevent unwanted data getting written into an unmounted mount point in those situations. I would still add the mount check to your scripts so that you can output meaningful errors though.

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  2. Why not just have the backup script test whether /backups is mounted, and exit if not?

    mount | grep -q /backups || exit 1
    • 6

  3. the easiest way to handle this is.. with rsnapshot directly.

    You should have a look at the option no_create_root

    HTH

    • 2