We cannot find this disk on CDM probe
/var/lib/pgsql
Release : 20.4
CDM version 6.71MC
Agent version 9.34.
The disk was ignored by ignore_filesystem regex. In cdm one can rt-click and delete the drives you've chosen to ignore, then restart or cold start, close and reopen the GUI and those filesystems/drives will not be discovered and they will remain ignored. The disk was thus deleted.
Removing the ignore_filesystem regex, and restarting cdm resolves this issue.