Volume Shadowing for OpenVMS is a System Integrated Product
(SIP) that you install at the same time that you install the operating
system. Volume Shadowing requires its own license that is separate
from the OpenVMS base operating system license. To use the volume
shadowing software, you must install this license. All nodes booting
from shadowed system disks must have shadowing licensed and enabled.
See the instructions included in your current OpenVMS upgrade and
installation manual.