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Using a remote command device

When you configure a remote command device in your storage system, you can perform operations in an externally attached storage system by issuing Command Control Interface (CCI) commands to the remote command device in your (local) storage system.

Overview of remote command devices

A remote command device is a volume that is used to transfer CCI commands to a command device on an external storage system. To use a remote command device, you map to an external volume that is already configured as a CCI command device on the external storage system. The mapped volume then becomes a remote command device.

After mapping to an external command device, you can issue CCI commands (for example, ShadowImage, TrueCopy, or other commands) to the remote command device in the local storage system. The CCI commands are relayed from the remote command device to the command device in the external storage system where they are executed, as shown in the following figure.

NoteWhen you map to an external command device, the license for Universal Volume Manager is not required.
GUID-5A9C9F19-C471-45A4-ABD7-A234902F7786-low.png

Requirements

The following table shows requirements for mapping a command device as a remote command device.

Item

Requirement

Number of LDEVs in an external volume

1

Cache mode

Disable

Minimum capacity

96,000 Blocks (about 47 MB)

Maximum capacity

4 TB

Maximum number of the available CCI instances per remote command device

16

However, the maximum number of available CCI instances might be less, depending on the number of paths between the local storage system and an external storage system.

Restrictions and other information

Before mapping a command device as a remote command device, note the following information.

  • The remote command device cannot be identified by port discovery or volume discovery process that takes place during the mapping operation.
  • When an external storage system (A) has a remote command device (B) (that is, when a command device in another external storage system (C) is mapped to this external storage system (A)), make sure that the remote command device (B) does not have the smallest LUN on the port in the external storage system (A).
  • You cannot send I/O to the remote command device.
  • You cannot receive I/O from the remote command device.
  • You cannot set command device disable on the remote command device.
  • You cannot set command device security on the remote command device.
  • Do not set the command device security on the external storage system side for the command device that is mapped as a remote command device.
  • You cannot create CVs using the VLL function in the remote command device.
  • Command device information reported to the local host by the remote command device includes the following:
  • Errors can occur when operations are performed on the remote command device, even though the status of the remote command device is normal. In this case, check the status of the command device on the external storage system where the error actually exists.

Remote command device information

To map a command device, select a command device that can be mapped and follow the procedure in Mapping an external volume .

After the remote command device is mapped, the device appears in the Device Name column of the Mapped Volumes window as follows:

Storage system

Information displayed in Device Name column

VSP G350, G370, G700, G900, F350, F370, F700, F900

VSP G200, G400, G600, G800, VSP F400, F600, F800

VSP G1000, G1500, VSP F1500

Virtual Storage Platform

Unified Storage VM

Universal Storage Platform V

Universal Storage Platform VM

SANRISE Universal Storage Platform

SANRISE Network Storage Controller

SANRISE9900V series

TagmaStore Universal Storage Platform

TagmaStore Network Storage Controller

Lightning 9900V series

Virtual Storage Platform VX7

VP9500

H24000

H20000

SANRISE H12000

SANRISE H10000

SANRISE H1024/H128

XP7 Storage

XP24000

P9500

XP24000

XP20000

XP12000

XP10000

XP1024/XP128

Format: "Emulation Type" + "-CM"

Example: OPEN V-CM

Unified Storage

Adaptable Modular Storage

Workgroup Modular Storage

SANRISE9500V series

Thunder 9500V series

DF600F-CM