Software User Manual

Figure 8 Alternate path mode is Single mode with alternate paths in Standby only

NOTE:

External arrays with Active/Standby (A/S) controllers, such as the MSA, are an example of Figure 8.

A notable characteristic of using A/S controller arrays as external storage is that there is typically

only a si

ngle port to the owning controller. Paths to the non-owning external controller's ports are

shown a

s Standby status. I/O load balancing does not occur across external controllers.

Powering arrays on or off

This section describes procedures for powering local and external arrays on or off after External Storage

XP operations have started.

The procedures below will utilize the following commands:

• Disconnect Subsystem

Execute the Disconnect Subsystem command from the Command View XP or XP Remote Web Console

GUI when you need to perform maintenance or stop the local or external array. This command stops

acceptance of all host I/O operations to the external LU mapped as the internal LDEV. All outstanding

data in cache memory on the local array intended for the external LU is written (de-staged) to the

external LU.

For instructions on executing the Disconnect Subsystem command, see Disconnecting external arrays

or LUs.

Preparing for External Storage XP operations