HP StorageWorks XP Remote Web Console Software - Manual (Page 18)

Figure 2 LU path configuration in Fibre Channel environments
.
Use XP LUN Configuration and Security Manager Software 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 XP LUN Configuration and Security Manager Software 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 XP LUN Configuration and Security Manager Software 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.
Overview of XP LUN Configuration and Security Manager Software 18