If you will be using Solstice DiskSuite, set aside a 10 Mbyte slice on the system disk for metadevice state database replicas. See your Solstice DiskSuite documentation for more information about replicas.
If you will be using VxVM, designate a disk for the root disk group (rootdg). See your VERITAS documentation for guidelines and details about creating the rootdg. Refer also to "VERITAS Volume Manager Considerations", for more information.