Lun Masking; Lun Masking (V3.X); Lun Masking (V2.X) - HP StorageWorks 6000 - Virtual Library System User Manual

To get around the maximum LUNs per device restriction, you can either:
• Increase the maximum LUNs per device setting for the operating system. See
"Troubleshooting" on page 311 for more information.
• Enable LUN mapping on the VLS to restrict the number of virtual devices the host's operating system
sees on the VLS Fibre Channel host ports. See
"LUN Mapping

LUN Masking

The method of LUN masking differs between VLS firmware versions 3.x and 2.x.

LUN Masking (v3.x)

LUN masking restricts a host's access to the virtual devices (virtual libraries and/or tape drives) on
the VLS. You should use it when there are more virtual device LUNs mapped to an Fibre Channel host
port than the operating system LUN restrictions support. You can limit the LUNs the host's operating
system can see on the port, so that only the virtual devices the host needs to see are visible.
For example, if a host's operating system is configured to only see up to eight LUNs per Fibre Channel
host port, the host will not be able to see the virtual devices numbered LUN8, LUN9, and up. Suppose
that you need the host to see LUN0 through LUN5, LUN8, and LUN9. You can enable LUN mapping,
thereby hiding all of the LUNs from the host. Then you can map LUN0 through LUN5, LUN8, and
LUN9 to the host. The VLS will automatically renumber the mapped LUNs so that LUNs 8 and 9
become LUNs 6 and 7 and they are now within the eight the host can see. See
"LUN Mapping
In the VLS, LUN masking occurs automatically for all hosts when you enable LUN mapping using the
global enable/disable LUN mapping setting. See

LUN Masking (v2.x)

By default all hosts on the SAN can access all the virtual libraries on the VLS. You can restrict a host's
access to the virtual libraries and/or tape drives (virtual devices) on the VLS by performing LUN
masking.
LUN masking should also be used when there are more virtual devices (LUNs) port mapped to a FC
host port than the operating system LUN restrictions support. This prevents the host's operating system
from seeing the virtual devices it needs to see on the port. For example, if a host's operating system
is configured to only see up to eight LUNs per FC host port, the host will not be able to see the virtual
devices numbered LUN8, LUN9, ..., and up. LUN masking limits the virtual devices (LUNs) the host's
operating system can see on the port, so that only the virtual devices the host needs to see are visible.
To perform LUN masking:
1. Open a Command View VLS session and log in as the administrator. See
"Opening a Command View VLS Session from a Web
2. Click the System tab.
3. Select Chassis in the navigation tree.
152 Configuration
(v2.x)" on page 159 for instructions.
(v3.x)" on page 153.
"LUN Mapping (v3.x)" on page 153 or
"Setting the Default LUN
Browser" on page 135.
Mapping" on page 153.