LUN Masking groups define the connection between the host initiators and the VT library devices (robots or tape drives). Devices which belong to a certain group can be seen by the host initiators of the group. A device can belong to multiple LUN Masking groups, but a host initiator can belong to only one LUN Masking group.
Select the Configure LUN Masking groups option from the VT > LUN Masking menu to begin configuring LUN Masking groups.
You can add LUN Masking groups. If a group exists, configure the group by adding Host Initiators, adding or modifying libraries, or adding or modifying the devices within the libraries.
Creating LUN Masking groups
Begin working with LUN Masking groups by adding a group via the LUN Masking window. A maximum of 512 groups can be configured per system and a maximum of 512 drives can be configured per group. (A maximum of 1024 host initiators can be defined on a system.) Each group needs to contain at least one host initiator and one device (tape drive or robot). Robots can be added as required.
To add a LUN Masking group:
- On the left side of the LUN Masking window, click Add at
the bottom of the LUN Masking Groups pane.
The group details appear to the right of the window. Figure 1. LUN Masking window
- Type a new name for the group in the Group name field.
- Add host initiators by clicking Add in the Selected Host Initiators pane. The Add Host Initiators dialog is displayed.
- Select the Host Initiators to add to the LUN Masking group from the list displayed and click Ok.
- Continue adding more host initiators, or go on to add the library devices.
- To define the devices, click Add at the bottom of the Library Mappings pane in the LUN Masking group details view. A list of libraries in the system is displayed.
- Select the relevant libraries from the list and click Ok
Continue selecting the library devices to be viewed by the host initiators in the group.
Modifying a LUN Masking group
From the Selected Devices pane, modify the libraries and devices defined in the LUN Masking group. Once you have finished, click Save changes to save your modifications and exit the LUN Masking configuration.
After modifying a LUN Masking group, undesired holes might occur within the LUN numbering sequence. For example, removing a device from an existing group causes holes in the LUN numbering if this device does not have the highest LUN number. As a result, the backup application might have trouble scanning the devices. If your backup application has trouble scanning the devices, it is recommended that you or renumber the LUN.
Reassign the LUNs by clicking Reassign All LUNs at the bottom of the Selected Devices pane. The system displays the Reassign LUNs dialog. You are about to renumber all the LUN values of the available devices in the group and rescan the connected hosts.
Click Yes to renumber. The LUN values are renumbered and all the devices in the Selected Devices pane are assigned new LUN numbers, sequentially, starting with “0” (zero).
Continue to the next section.
Removing a LUN Masking group
If a LUN Masking group is removed while LUN Masking is enabled, the host initiators of that group become ineffective. They are unable to "see" any devices on this system. The host initiators must be reassigned to a different group to be reconnected.
To remove a LUN Masking group, click Remove at the bottom of the LUN Masking groups pane. The LUN Masking group is removed from the list.
Continue configuring the LUN Masking groups as appropriate. Click Save changes to save your modifications and exit the LUN Masking configuration.