About Universal Volume Manager Operations 2-21
Hitachi Universal Storage Platform V/VM Universal Volume Manager User’s Guide
You can set in advance the mapping policy on whether to execute the Port
Discovery automatically or manually. If Port Discovery is executed
automatically, WWNs connected to all the external ports of the local storage
system will be searched for. If Port Discovery is executed manually, you can
select a specific external port and limit the scope to search WWNs. If you can
specify which external port to search for, you can reduce the operation time by
executing the Port Discovery manually.
Volume Discovery is a process to search for and get information about external
volumes from the target ports of the external storage system. Volume
Discovery is automatically executed after the Port Discovery process.
Note: When a port in an external storage system is connected to USP V/VM
and has a management LU (for example, Universal Xport LU), an extra
operation is required. A management LU is an LU that receives commands
issued by a particular application. The management LU controls or manages
that application. The management LU stores control information from that
application and therefore the management LU cannot be used as an external
volume. A command device is not a management LU.
Before performing port discovery or volume discovery, perform one of the
following operations on the external storage system.
• Delete the management LU from the port connected to USP V/VM.
• Make sure that at least one LU is used for data storage and has a smaller
LUN than the LUN of the management LU. Also make sure that the data
storage LU is set to the port connected to USP V/VM.
• Use the security function and configure the access attribute of the
management LU to prohibit read and write operations.
If none of the above operations are performed, an external storage system
that has a management LU might not be recognized by the local storage
system.