HP 12000 Design Manual page 41

Figure 15 Virtual Tape Environment
In the VLS firmware version 1.x/2.x, the LUN mapping mode is specific to each host. It lets you
manually assign new LUN numbers to the virtual devices visible to the host, and hosts that are not
LUN masked continue to use the default (shared device) LUN numbering. In the firmware versions
3.x and higher, the LUN mapping mode is a global setting across the entire device, and when
LUN mapping is enabled all hosts will only see the virtual devices presented to those hosts (so by
default any new host will see no virtual devices). Also, in versions 3.x and higher the LUN numbering
is automatically generated for any virtual devices presented to a host.
Backup SAN Design Guidelines 41