HP XP LUN Configuration and Security Manager Software - Manual (Page 12)

12 LUN Manager for the XP10000/XP12000
00:01, and 00:02. LU paths are defined between the two hosts in the hg-lnx group and the three logical
volumes.
Figure 1 LU paths configuration in a Fibre Channel environment
LUN Manager lets you define paths between a single server host and multiple LUs. In Figure 1 , both hosts
in the hg-lnx host storage domain can access the three available LUs.
LUN Manager lets you define paths between multiple server hosts and a single LU. In
Figure 1 , the LU
identified as CU-LDEV 00:00 is accessible to the two hosts in the hg-lnx host storage domain.
In
Figure 1 , the LUs associated with the hg-lnx domain are addressed by numbers 0 to 2. The address
number of an LU is referred to as the logical unit number (LUN). When HP StorageWorks Continuous
Access XP and other optional features manipulate LUs, they use LUNs to specify the LUs to be manipulated.
You can add, change, and delete LU paths when the system is operational. For example, if new disks or
server hosts are added to your disk array, you can add new LU paths. If an existing server host is to be
replaced, you can delete the corresponding LU paths before replacing the host. You do not need to restart
the system when you add, change, and delete LU paths.
If a hardware failure (such as a CHA failure) occurs, there is a chance that some LU paths are disabled
and some I/O operations are stopped. To avoid this, the system administrator can define alternate LU
paths. If one LU path fails, the alternate path takes over the host I/O.
In a Fibre Channel environment, up to 1,024 LU paths can be defined for one host storage domain. Up to
1,024 LU paths can be defined for one port.
NOTE: You cannot define an LU path to LUN On Demand volumes or volumes reserved by Auto LUN XP.
• Up to 256 host storage domains can be created for one Fibre Channel port. Up to 57,344 host storage
domains can be created for one disk array. The maximum number of ports per subsystem is 224.
Port
Host Storage Domain
Host Groups