HP StorageWorks XP Remote Web Console Software - Manual (Page 19)

LUN Configuration and Security Manager XP user guide for the XP12000/XP10000/SVS200 19
After classifying server hosts into host groups, you must associate the host groups to logical volumes. In
Figure 2 , the hg-lnx host group is associated with three logical volumes (00:00, 00:01, and 00:02). LU
paths are defined between the two hosts in the hg-lnx host group and the three logical volumes.
Figure 2 LU path configuration in Fibre Channel environments
Use LUN Manager to define paths between a single server host and multiple LUs. In Figure 2 , both hosts
in the hg-lnx host group can access the three LUs.
Use LUN Manager to define paths between multiple server hosts and a single LU. In
Figure 2 , the LU
identified by CU-LDEV number 00:00 is accessible from both hosts belonging to the hg-lnx host group.
In
Figure 2 , LUs associated with the hg-lnx host group are addressed by numbers 0000 to 0002. The LU’s
address number is referred to as the logical unit number (LUN). When Continuous Access XP and other
optional programs manipulate LUs, the programs use LUNs to specify the LUs to be manipulated.
You can add, change, and delete LU paths when the system is operating. For example, if you add new
disks or server hosts to the array, you can add new LU paths. If you replace an existing server host, you
can delete LU paths corresponding to the host before replacing the host. You do not need to restart the
system when you use LUN Manager to add, change, and delete LU paths.
If a hardware failure (such as a CHA failure) occurs, some LU paths might be disabled and some I/O
operations might be stopped. To avoid this situation, the system administrator can define alternate LU
paths. If one LU path fails, the alternate path takes over the host I/O.
For more information, see:
• ” Defining LU paths ” on page 75
• ” Changing or viewing LU path settings ” on page 84