Overview of Universal Volume Manager

REST API Reference Guide for Virtual Storage Platform 5000, Virtual Storage Platform E Series, and Virtual Storage Platform G/F Series

Version
93-07-0x
90-09-0x
88-08-10
Audience
anonymous
Part Number
MK-98RD9014-17
Universal Volume Manager is a function that virtualizes storage devices and enables different models of storage systems to be used as one storage system.

To use volumes on an external storage system as external volumes, use a cable to connect the external connection port of the local storage system and the port of the external storage system, and then allocate (map) the volumes of the external storage system to the local storage system.

External volumes are used in situations such as the following:
  • When you want to back up data in the volumes on the local storage system to the external storage system
  • When you want to allocate an external volume to a host when the host issues a request for a volume to be used for storing data
  • When you want to migrate data from the old storage system (external storage system) when a new storage system is installed

To discontinue the use of an external storage system that has become necessary, unmap the volumes of the unnecessary external storage system.

For details about the functions of Universal Volume Manager and related notes, see the Hitachi Universal Volume Manager User Guide.

The following figure shows the system configuration for using Universal Volume Manager, and the components of that configuration.

Local storage system

The local storage system receives requests from the REST API client.

External storage system
The external storage system is connected to the local storage system via external paths.
External path
An external path is a route by which the external connection port of the local storage system and the port of the external storage system are connected. You can set multiple routes as external paths. A group consisting of multiple external volumes that use the same external path is called an external path group.
External parity group
An external parity group is used to manage external volumes on the local storage system. Although an external parity group does not include parity information, it is managed in the same way as a parity group is managed. By registering external volumes on the external storage system in the external parity group, you can use the external volume from the local storage system.
External volume

You can enable volumes on an external storage system to be used from the host by creating external volumes from the external parity group. You can use the external volumes in the same way as other volumes on the local storage system.

Tip:

The mapped volumes on the external storage system are also called external volumes. When these mapped volumes need to be distinguished from the external volumes that are used on the local storage system, the mapped volumes will be referred to as "external volumes on the external storage system".

Important:
If you are using the REST API, Storage Advisor Embedded, or CCI, attempts to perform multiple, concurrent executions of the following operations on external volumes might fail or produce incorrect results.
  • Getting a list of ports on an external storage system
  • Getting a list of the LUs of ports on an external storage system
  • Getting information about the iSCSI targets of ports on an external storage system
  • Performing a test to log in to an iSCSI target of an external storage system registered to the port of the local storage system
We recommend that you do not perform multiple, concurrent executions of these operations. For details about the problems that might occur if you perform multiple, concurrent executions of these operations and how to resolve these problems, see the note on the number of concurrent executions of operations on external volumes in the Hitachi Universal Volume Manager User Guide.