Use the -o option to check for SCSI-3 reservation or registration compliance but not to test the disk size requirements.
Note that you can override a disk size-related error by using the -o flag. The -o flag lets the utility continue with tests related to SCSI-3 reservations, registrations, and other tests. However, the disks may not set up correctly as the disk size may be below the supported size for coordinator or data disks.
You can use the -o option with all the available vxfentsthdw options when you encounter size-related errors.