From the VM:Secure Administration Guide:
CA VM:Secure rewrites the volume allocation map on the object directory volume each time a directory is updated, caching information from that area.
To change anything affecting cylinder 0 of the volume, such as reallocating the volume using the CPFMTXA utility or relabeling the volume, perform the following steps:
1. Bring CA VM:Secure down.
2. Perform the activity to change the allocation map or label of the volume.
3. To have CA VM:Secure pick up the new allocation information, reinitialize CA VM:Secure using the SOURCE operand.