This fault occurs when storage capacity utilization is greater than 90%. You definitely need to clean up the storage to avoid logging messages not being logged anymore or (sometimes) unexpected issues like system reboot.
To resolve the problem:
- Cleanup any files created by the user, if any, on the partition on the storage device that the fault was produced on to free up space
- Cleaning of any old core files (which are not needed for any investigation) can be accomplished as follows: In the UI, go to Admin - Import/Export - Export Policies - Core - default - Operational, then click on old core files which are not needed for further use and delete.
- Cleaning of techsupport files can be accompolished as follows: In the UI, go to Admin - Import/Export - Export Policies - default - Operational, then click on individual techsupport files and delete.
- If the above action did not resolve the issue, create a tech-support file and contact Cisco TAC. Alternatively, you can simply perform a reload of the device, which clears the temporary files.
Stay safe,
Sergiu