Have you checked VCS Bundled Agent Guide for your VCS version?
I would start here in this doc:
Notes for DiskGroup agent
The DiskGroup agent has the following notes:
■ Using volume sets
Using volume sets
When you use a volume set, set StartVolumes and StopVolumes attributes of the
DiskGroup resource that contains a volume set to 1. If a file system is created on
the volume set, use a Mount resource to mount the volume set.
See the Mount agent description for more information.
The VolumeSet agent brings online, takes offline, and monitors a Veritas Volume
Manager (VxVM) volume set. Use the agent to make a volume set highly available.
Dependencies for VolumeSet agent :
(see the manual for diagram)
Bundled agent guide for your VCS version can be found here: