Symptom

Different symptoms can appear because of that issue, depending on how full the disk is:

unable to commit the configuration
unable to download the new update (dynamic update and/or software update)
unable to download software updates for managed Firewalls due to Error:

Error: There is not enough free disk space to complete the desired operation.
Delete older software, dynamic update, or client versions to free additional disk space before trying the operation again.
Use the 'set max-num-images count' CLI command to adjust the number of versions stored in order to avoid this problem in the future.

The /opt/pancfg partition usage is over 75%

Panorama> show system disk-space
Filesystem      Size  Used  Avail Use% Mounted on
/dev/sda2       3.8G  2.8G 822M 78% /
/dev/sda5       7.6G  5.4G 1.8G 75% /opt/pancfg        <----- /opt/pancfg
/dev/sda6       3.8G  1.3G 2.3G 37% /opt/panrepo
tmpfs           1.9G  110M 1.8G 6% /dev/shm
cgroup_root     1.9G     0 1.9G 0% /cgroup
/dev/sdb1       20G   12G  6.9G 64% /opt/panlogs

Environment

Panorama VM in legacy mode on VMware ESXi
PAN-OS. 8.1 and above.

Cause

The /opt/pancfg partition is small (7GB) and getting filled quickly. This is common on Virtual Panorama's deployed in Legacy Mode with smaller disk partition causing the /opt/pancfg to fill up quicker.

Resolution

There are 2 solutions for this issue:

Clear the disk
Increase the disk space

Solution 1 - Clear the disk

From the WebUI, go to the following sections to remove unused software

Panorama > Software
Panorama > Dynamic Updates
Panorama > Device Deployment > Software
Panorama > Device Deployment > Dynamic Updates

To clear a specific software, go to the right category then click on the cross

If after removing that software, the issue is not resolved yet, please contact directly the Support to clear additional content.

Solution 2 - Increase the disk space

To resolve definitively this issue, we will install the system on the 81GB disk space. 81GB is the required disk space for the system to move to panorama mode.

Turn off the Panorama VM
Go to the menu to edit the VM settings

Add a new disk to the Panorama VM.

Set the following parameters for the new disk
- Disk size: 81GB
- Disk Provision: Thick Provision
- Virtual Device Node: SCSI

Click OK when done.
Power On the Panorama VM
From the CLI, look for the new disk name using the CLI command "show system disk details" (in the example, the name is sdb)

Once the disk is located, and you got the name of it, launch the copy of the system disk to this new disk using the command "request system clone-system-disk target <name>" (in the example sdb)

Note: The information is available only on Console. The copy process takes time (around 30 min) during which the Panorama reboots. When the process is finished, the system ask you to shut down the Panorama.

Turn off the Panorama VM - Go to the menu to edit the VM settings
Remove the original system disk from the virtual machine
Change the new system disk Virtual Device Node to SCSI(0:0)
Power on the Panorama VM

Additional Information

From PAN-OS 9.1, the system disk should be increased to 224GB.

Increase the System Disk on the Panorama Virtual Appliance

High Disk Utilization on /opt/pancfg partition on Virtual Panorama