One or more Ceph Monitors are low on disk space.

This alert triggers if the available space on the file system storing the monitor database as a percentage, drops below mon_data_avail_warn (default: 15%). This may indicate that some other process or user on the system is filling up the same file system used by the monitor. It may also indicate that the monitor’s database is large.

Note: The paths to the file system differ depending on the deployment of your mons. You can find the path to where the mon is deployed in storagecluster.yaml.
Example paths:
  • Mon deployed over PVC path: /var/lib/ceph/mon
  • Mon deployed over hostpath: /var/lib/rook/mon
In order to clear up space, view the high usage files in the file system and choose which to delete. To view the files, run:
du -a <path-in-the-mon-node> |sort -n -r |head -n10
Replace <path-in-the-mon-node> with the path to the file system where mons are deployed.