Mapping an external volume

You can use the information in this topic to map an external volume as an internal volume.

Prerequisites

Attributes set for the external volume before mapping, such as port security, LUN security, Volume Retention Manager attributes, and so on are discarded when the external volume is mapped. If the original attributes are required, reset them in the local storage system after mapping.

When the external volume is a command device, it is mapped as a remote command device. For important information about mapping command devices, see the Hitachi Universal Volume Manager User Guide.

Before you map the external volume, check whether any application is using the volume. If so, stop the application before mapping.

For example, if mapping a command device, make sure CCI commands are not being executed during the mapping operation.

When you create an LDEV at the same time that you map an external volume, you cannot select the following LDEV numbers:

Numbers already in use.

Numbers not assigned to the user.

You must have Storage Administrator (Provisioning) role to perform this task.

Procedure

Open the External Storage window.

In the Hitachi Command Suite:

On the Resources tab, click Storage Systems, and then expand All Storage Systems.

Expand the target storage systems, right-click External Storage, and then select System GUI.

In Device Manager - Storage Navigator:

Click Storage Systems, and then expand the Storage Systems tree.

Click External Storage.

On the External Storage Systems tab, click Add External Volumes.

In the Add External Volumes window, add the external volume by clicking either By New External Path Group or By Existing External Path Group.

To add the external volume By New External Path Group:

a. Click Create External Path Group.

b. In the Create External Path Group window, enter the following:

— Initial External Path Group ID. The storage system searches IDs from the initial ID you specify in ascending order and allocates an ID that can be used. The default range that you can specify is from 0 to 2,047 for VSP G200, 0 to 4,095 for VSP G400 and VSP G600, and 0 to 14,079 for VSP G800.

— External Paths. If you do not see the port or WWN you want in the Available External Paths box, click Discover External Target Ports. In the new window, select the desired ports and click Add, then click OK.

— External Storage System. If the external system is not selected, scroll down the list and select it.

— Available External Paths. Select the desired port IDs and click Add, then click OK.

c. Set the priority for a path by selecting it and clicking Raise Priority or Lower Priority.

d. Click OK.

To add the external volume By Existing External Path Group:

a. Click By Existing External Path Group.

b. If you have not identified the external storage system that you want to connect the external path to, click the storage system button and select the system.

c. In the Available External Paths list, select the desired path group. Path groups consist of the external paths previously set up and prioritized.

d. Click Next.

In the Add External Volumes window’s Discovered External Volumes box, select the desired external volumes.

In Initial Parity Group ID, enter an external volume group number and sequential number. A group allows you to place similar external volumes in a group; for example, volumes used for a copy function.

The range is from 1 - 1 to 16384 - 4096.

In Allow Simultaneous Creation of LDEVs, select Yes to allow the system to automatically create LDEVs in the external volume, otherwise select No.

If the external volume is a command device, select Yes in both Allow Simultaneous Creation of LDEVs and Use External Storage System Configuration.

In Use External Storage System Configuration, select Yes to use the external storage system’s configuration when the local system create LDEVs (if Allow Simultaneous Creation of LDEVs is also Yes). Otherwise, select No.

If the capacity of the external volume is over 4 TB, select Yes in Allow Simultaneous Creation of LDEVs and No in Use External Storage System Configuration. Then enter the number of LDEVs to be created in Number of LDEVs per External Volume. Several LDEVs (maximum of 4 TB, up to the number indicated in Number of LDEVs per External Volume) will be created. If the external volume is a command device, the LDEV will be mapped as a remote command device.

If the external volume is a command device, select Yes in both Allow Simultaneous Creation of LDEVs and Use External Storage System Configuration. Cache mode for the remote command device will be Disabled regardless of the selection in Cache Mode.

In LDEV Name, enter the prefix character and the initial number.

The entire value can be a maximum of 32 characters including the initial number (numerical value of 9 digits or less), or blank. Blank is displayed by default. Note the following numbering rule:

1:total 9 numbers (1,2,3,…9)

08:total 92 numbers (08,09,10,…99)

23:total 77 numbers (23,24,25,…99)

098:total 902 numbers (098,099,100…999)

Click Options (if not already expanded). If you have previously edited mapping settings (policies), you may not want to change the options. However, review the following steps—since some fields in Options are affected by preceding steps.

In the expanded Options box, for Initial LDEV ID enter the initial LDEV ID for the external volume. The local storage system searches from this number in ascending order and allocates the next available ID. You can review used, available, and disabled LDEVS by clicking View LDEV IDs.

For LDKC, enter 00.

For CU, enter the CU number, which can be from 00 to 07 for VSP G200, from 00 to 0F for VSP G400 and VSP G600, from 00 to 3F for VSP G800. 00 is the default.

For DEV, enter the LDEV ID, which can be from 00 to FF. 00 is the default.

For Interval, enter an interval between LDEV IDs, which can be from 0 to 255. 0 is the default.

In Number of LDEVs per External Volume, enter the number of LDEVs to be created when the external volume is mapped. This field is greyed out if you selected Yes in Allow Simultaneous Creation of LDEVs and Use External Storage System Configuration, and 1 displays

In Cache Partition, select the CLPR for accessing the mapped external volume.

For more information about the Cache Partition, Cache Mode, and Inflow Control settings, see Editing mapping policies .

In Cache Mode, click Enable to propagate write data asynchronously from cache to the external storage system. Click Disable to propagate data synchronously.

When the external volume is a command device, Cache Mode for the remote command device is automatically set to Disable regardless of your setting.

Data that is not written by the host (for example, data written by pair operation) is asynchronously destaged to the external storage system regardless of the Cache Mode setting.

In Inflow Control, click Enable to limit or prevent write data from being written to cache memory when the write operation to the external volume cannot be performed. Click Disable to allow write data to be written to cache.

In MP Unit ID, select the MP unit ID for the external volume. MP unit assignment should evenly distribute work across the available processors.

The range is from MPU-10, MPU-11, MPU-20, or MPU-21. The value depends on the configuration of the device.

Select Auto (the default) to cause an MP unit ID to be automatically assigned by the system. If Auto cannot be selected, the MP unit ID with the lowest number is selected by default.

Click Add.

If you need to change the added volume’s settings, in the Selected External Volumes list click the volume, click Change Settings, make necessary changes, and click OK.

To to add LUN paths, click Next in the Add External Volumes window. See the Hitachi Virtual Storage Platform G200, G400, G600 Provisioning Guide for information.

Click Finish when ready.

In the Confirm window, check all settings, accept or enter a new task name.

When you select the external volume and click LDEV Detail, the External LDEV Properties window is displayed for you to check the LDEV information.

In the Confirm window, click Apply. The setting is queued as a task and it is performed in order.

Open the Tasks window to verify the result of the operation. A task can be suspended or canceled if the process has not started.