local storage system. After the mapping, you can manipulate the external volume from the local storage system in the same way as manipulating an internal volume.

When external volumes in external storage systems are mapped as internal volumes in your storage systems, the external volumes can be accessed and copied by hosts connecting to your storage systems, but not by hosts connecting to the external storage systems.

This document sometimes uses the term external volume or mapped external volume to mention an internal volume where an external volume is mapped (see B in Figure 4 (page 14)), because this internal volume is a virtual representation of an external volume.

When you perform mapping, a path is automatically created between an internal volume and an external volume. This path is called a mapping path, which connects one volume with another volume. A cross-subsystem path is a part of a mapping path.

To use the external volumes that you mapped as an internal volume (see B in Figure 4 (page 14))

-from the host or other program products, the system administrator needs to create LDEVs in the external volume (see A in Figure 4 (page 14)). To create LDEVs, use XP External Storage at the time of mapping, or use the Virtual LVI/LUN (VLL) function on the internal volume where an external volume is mapped after mapping. The LDEVs created by these methods are called LDEVs in the external volume in this document. These LDEVs are usually called external volumes in other documents.

An external volume corresponds to a VLL VDEV (Virtual Device). An LDEV in the external volume corresponds to a VLL LDEV. Therefore, you can use the VLL function to create custom-sized volumes in an external volume after mapping, in the same way as creating custom-sized volumes in the normal internal volumes. For details on VDEVs and LDEVs, see the HP StorageWorks XP24000/XP20000 Virtual LVI/LUN (VLL) and Volume Shredder User Guide.

XP External Storage Operations

Use XP External Storage to execute the following operations.

•Preparing to use external volumes

You can map external volumes, set port attributes, and set cross-subsystem paths. For details, see “Configuring XP External Storage” (page 16) and “Overview of Setting Operations” (page 65).

•Preparing to manipulate the power supply of the storage systems

You must follow specific procedures to manipulate the power supply of the storage systems when external volumes are used. To turn on or off the power supply of the external storage system after starting to use the external volumes, you need to execute the commands of XP External Storage. For details, see “Turning On or Off the Storage System” (page 88).

•Setting up and removing the cross-subsystem paths

When you set up or remove the path (cable) connecting the storage systems, you need to use XP External Storage to make settings on the path. For details on removal, see “Disconnecting External Storage System or Disconnecting External Volume” (page 91) and “Checking Connection Status and Resuming External Volume Operation” (page 93). For details on setup, see “Configuring the Cross-subsystem Path” (page 81).

•Referring to the status of external volumes

You can see the status and the configuration of external volumes. For details, see “Checking the External Volume Details” (page 85).

•Stopping the use of external volumes

You can cancel mapping of external volumes. For details, see “Deleting the External Volume Mapping (Delete Volume Command)” (page 99).

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