How get rsync to write only to USB disk, and fail if it's not mounted?

Question

Ubuntu 9.10, connected to external WD 1.5GB USB drive, called "data_3"

I connected the USB cord and all was well for a long time. Ran nightly cron jobs rsyncing data via the internal network.

After a powerout, after which the external USB did not start, the rsync job COPIED the data to /media/data_3, on the INTERNAL drive which is much smaller and ran out of space.

The rsync script points to the supposedly mounted USB drive at /media/data_3, but when it does not exist it writes to /media/data_3, on the internal drive.

How get rsync to write only to the USB disk, and fail if it's not mounted ?

Answer 1

You'll need to check beforehand if the disk is mounted (via mount and grep), and then have the script fail if it is not.

Answer 2

You can create a file on the external drive and test for its presence before running rsync.

if [ -e /media/data_3/testfile ]; then rsync /source/directory /media/data_3/destination; fi should work as a one line in bash at least. You can add an else condition to send you a mail if the file doesn't exist (meaning the partition isn't mounted, or isn't mounted in the right place).

Answer 3

Something I tried a few years ago now, was to make the mount point directory read only so that if the device wasn't present, the copy would fail. I think it also meant that I had to include the device in fstab and mount it manually if plugged in after booting.