Your disk is full and empty
August 14, 2022
I recently had a Schrödinger’s cat experience with the root
drive of my NAS. Suddenly, I wasn’t able to apply any system
updates to the system while getting errors indicating my root drive
was full, which was strange as a 32G drive should be more than
sufficient for storing the system. When checking the file
To confirm that my disk indeed had unallocated space, I also
checked the allocation using
What was going on?
The next thing I tried was to delete file caches and logs from
various places, and even after that,
After unmounting that disk and listing the contents of the directory acting as the mount point, I saw what was allocating the disk space.
The way I was backing up the SD card had a major flaw considering that the destination of the backup was on a mounted disk, or rather a memory stick. I hadn’t taken into account that the memory stick could either fail or, for some other reason, not be mounted while the backup was taking place. My solution was to first make sure that the disk was in fact mounted before performing the backup. I changed the cron job from this
Since then, the cron job has done what it was supposed to do. I was once again reminded of how a simple solution to a simple, but seemingly illogical problem, can seem to be impossible to find from an initial look.