Managing Virtual Device Access

Managing Virtual Device Access
	Chapter 2. Configuring a NearStore VTL Appliance

The Managing Virtual Device Access screens include:

SCSI Addresses Screen

Although the SCSI Addresses screen is not specifically a monitoring screen, it provides SCSI address information for the NearStore VTL appliance and for each virtual library and virtual tape device, that you have added to its configuration.

You can use this screen to gain information, such as the Logical Unit Number (LUN) of a device. This information can then be used when you add one of these devices to the configuration of the backup application.

From the Configuration Tasks menu, located on the left side of the screen, click Virtual Device Access.

The SCSI Addresses screen appears and the following information is provided:

Device Name—provides the name of the tape device.

Device Type—specifies the device type. If the device is the robotic arm of a library, Robot is displayed. If the device is a tape drive, Tape Device N, where N represents the number of the drive, is displayed.

Vendor ID—provides the vendor information for the tape device. This information is important because it is needed by the backup application when working with the device.

Product ID—provides the product information for the tape device. Along with the vendor information, the product identification is needed by the backup application when working with the device.

Port—specifies the port on which the device is available.

LUN—gives the LUN of the device. As already stated, this information is important when adding the device to the configuration of the backup application. Each physical Fibre Channel port in an system is a different target, but the virtual devices (possibly multiple libraries) are LUNs on that target.

Listing Ports

You can view a table of information about the ports. The information includes:

Port name
Port WWNN
Port WWPN
Topology
Node ID
Loop ID

Complete this task to view port information:

From the Configuration Tasks menu, located on the left side of the screen, click the Virtual Device Access task category.
Click the Port List tab, located in the upper portion of the screen.

The Port List screen appears.

Assigning Device Access

Once you have enabled the device access feature and added hosts and virtual libraries to the configuration of the NearStore VTL appliance, you can map these hosts to the virtual libraries.

Complete this task to assign hosts to virtual libraries.

From the Configuration Tasks menu, located on the left side of the screen, click the Virtual Libraries task category.
Click the Host Access tab, located in the upper portion of the screen.

The Host Access screen appears and the virtual libraries that are configured for the system appear.
From the Library Name field, click the name of the desired virtual library.

The Host Access screen appears.
Select the type of access that the host or hosts will have to the virtual library, specified in the Library Nickname field.

Valid types are:

Dedicated Library—when in this state, the virtual library can be accessed only by the host that is displayed in the Host Name field.

Shared Library—when in this state, the virtual library can be accessed by only the hosts listed.
From the Host drop-down menu, select the name of the host that you want to map to the virtual library, specified in the Library Nickname field.

(Optional) You can also select <New Host> to invoke the Add Host screen.
Click Apply to map the selected host to the specified virtual library.

Working with Port Assignments

If the NearStore VTL appliance uses more than one front-end port, you can map virtual libraries and drives to specific ports. When you are using port mapping, only hosts that are connected to a specific port (directly or through a switch) can see its assigned virtual libraries and drives.

You can map virtual libraries to ports when you first create the virtual library or after you create it. This allows for maximum flexibility. See Working with Virtual Libraries for more information on creating virtual libraries.

This subsection provides the following:

Viewing Existing Port Assignments

The NearStore VTL displays existing port mappings, including the name of the front-end port, the port World Wide Node Name (WWNN), World Wide Port Name (WWPN), topology, node ID, and the loop ID, on the Port List screen.

You can access the Port List screen from Configuration Tasks > Virtual Device Access > Port List.

Port Name—gives the name of the port.

Port WWNN—provides the WWNN of the port.

Port WWPN—gives the WWPN of the port.

Topology—provides the way in which the ports are connected to the SAN.

Node ID—gives the node identification for the port.

Loop ID—provides the loop identification for the port.

Creating/Editing Port Assignments

When using port assignments, you can either assign a complete library or the individual components (virtual tape drives and robots) of a library to specific ports.

For example, if you are using a virtual library based on the 7440 virtual library type, the library has four virtual tape drives. If your system has two front-end ports (port0 and port1) you can map drive0 and drive1 to port0. You can then map drive3 and drive4 to port1.

This provides a more detailed mapping of logical devices and enhances the NearStore VTL load-balancing capabilities.

Complete the following to map front-end ports to virtual libraries:

From the Configuration Tasks menu, located on the left side of the screen, click the Virtual Device Access task category.
Click the Port Assignment tab, located in the upper portion of the screen.

The Port Assignment screen appears and the NearStore VTL displays the following:

Library Name—provides the name of the virtual library that you can map to the front-end port.

Device—specifies the type of device that you can map to the port (the NearStore VTL displays Robot and Drives for each configured virtual library). If the virtual library has been broken down into its components, the NearStore VTL displays each component (drives and the robot) as individual devices.

Port—specifies the port to which the device is currently mapped.
From the Library Name field, click the name of the virtual library that you want to assign to a port.

By default, the NearStore VTL displays the single-port version of the Port Assignment screen. This version includes the option to keep the library as a single unit or to break it down into its components. It also includes a drop-down menu from which you can map the library to either a single or multiple ports.
(Optional) if you want to break the library into smaller components or assign it to multiple ports, select the Multi-Port option.
From the Port drop-down menu, select the port to which you want to map the virtual library.

If you selected the Multi-Port option, the NearStore VTL displays each drive and robot with a port drop-down. You can use this menu to map the component to a specified drive.
After you have made the selections, click Apply to map the library or library components to the specified drive or drives.

The NearStore VTL maps the selection to the port that you specified. The Port List screen reflects these changes.


Chapter 2. Configuring a NearStore VTL Appliance		Working with Virtual Tapes