HP XP Racks - Manual (Page 90)

•
Route label("Label" in the figure) – A label added to select the command device lines to be
used when multiple command device lines are defined for a route (see
Figure 47 (page 92) ).
A route label is not necessary if only one command device line is defined for a route.
•
APID – An ID used for communication between command devices. A unique APID within a
storage system is assigned to each command device line (see
Figure 47 (page 92) ). Note that
if command device lines have the same first command device, the command devices have the
same APID.
Command devices of the command device lines for reverse-direction routes have different
APIDs from the APIDs used for the command device lines for forward-direction routes.
•
Host ID – The unique ID used by a storage system to distinguish hosts when a command device
is shared among multiple hosts (multiple instances of operating systems). For details about
host IDs, see
“Configurations for which the same command device is shared from multiple
hosts” (page 743) .
Functions for minimizing CLI command execution time when using the Remote DKC
Control function
To minimize CLI command execution time when using the Remote DKC Control function, consider
the following settings:
•
Defining multiple command device lines
•
Creating inter-control unit logical paths dedicated to the command device
Defining multiple command device lines
If a command device line is defined for a route, access is concentrated on the command device.
As a result, I/O processing might take some time and response performance might degrade. These
problems can be eliminated by defining multiple command device lines for a single route. Multiple
command device lines, when defined, can be used as follows:
•
As multiple command device lines for CLI commands
•
As different command device lines for multiple replication tasks
Using multiple command device lines for CLI commands
If you define multiple command device lines in a configuration in which the Remote DKC Control
function is being used, access to command devices for CLI commands is distributed. This reduces
access to specific command devices, and a reduction in the CLI command response time can be
expected.
To use multiple command device lines, when defining the route list, omit the route label of the
command device lines to be used. Also omit the route label when loading the route list.
TIP: Alternatively, when defining the route list, you can add the same route label to multiple
command device lines to be used. Specify that route label when loading the route list.
The following figure provides an overview of using multiple command device lines for CLI commands.
90 Understanding Business Continuity Manager functions