Role of processor value units in assessing licensing requirements

Review the following procedure to understand how Tivoli Storage Manager estimates PVUs. The procedure also describes the steps that you can take to make the estimates more accurate.

1. When you install the Tivoli Storage Manager V6.3 server, or upgrade the server from a previous version, Common Inventory Technology is installed automatically. Common Inventory Technology is a software component that collects the metrics that are used to calculate PVUs.
2. When Tivoli Storage Manager clients connect to the Tivoli Storage Manager server, the clients send Common Inventory Technology information to the Tivoli Storage Manager server. This information includes the number of client and server devices, the number of physical processors, the processor vendor and type, and related information. The server will estimate PVUs only for nodes that are classified as server nodes. If you change the default classification for a device, the classification that you specify is used for PVU estimation. For more information about devices and nodes, see Device classification.
   Tip: Common Inventory Technology is not installed automatically on client nodes that are running on Linux operating systems. If you plan to obtain PVU information from a client node that is running on a Linux operating system, install Common Inventory Technology on the client node. For details, see Install the UNIX and Linux backup-archive clients.
3. The Tivoli Storage Manager server stores the information in the Tivoli Storage Manager database.
4. The Tivoli Storage Manager server generates PVU estimates. The estimates are based on the values that are stored in the Tivoli Storage Manager database and on PVU values that are defined for each processor type in the IBM_ProcessorValueUnitTable.xml file. The IBM_ProcessorValueUnitTable.xml file is installed automatically during the Tivoli Storage Manager server installation. You also can download the latest version of the file from an IBM FTP site. For more information, see Estimating processor value units.
5. You can browse PVU information by issuing commands that provide PVU estimates. For more information about obtaining and adjusting PVU estimates, see Estimating processor value units.

For purposes of PVU calculation, you can classify devices, such as workstations and servers, as client nodes, server nodes, or other. By default, devices are classified as client or server:

Client

Backup-archive clients that run on Microsoft Windows 7, Microsoft Windows XP Professional, and Apple systems are classified as client devices.

Server

Backup-archive clients that run on all platforms except for Microsoft Windows 7, Microsoft Windows XP Professional, and Apple systems are classified as server devices. All other node types are also classified as server devices. The server on which Tivoli Storage Manager is running is classified as a server device.

You can change the node classification to reflect how the device is used in the system. For example, if a node is classified as a server, but functions as a client, you can reclassify it as a client. If a node is not used in the system, you can reclassify it as other.

The PVU calculations are estimates because the software cannot determine all of the factors that are required for a final number. The following factors affect the accuracy of the calculations:

• PVU estimates are provided only for Tivoli Storage Manager V6.3 server devices that have established a connection with the Tivoli Storage Manager server since the installation of or upgrade to Tivoli Storage Manager V6.3.
• The default classification of nodes is based on assumptions, as described in Device classification.
• The PVU estimate might not reflect the actual number of processors or processor cores in use.
• The PVU estimate might not reflect cluster configurations.
• The PVU estimate might not reflect virtualization, including VMware and AIX® LPAR and WPAR.
• Common Inventory Technology might not be able to identify some processors, and some processors might not have corresponding entries in the PVU table.

You must have the following information to calculate PVUs:

• The node classification. PVUs are calculated only for server devices.
• The number of processors on the node.
• The processor vendor, brand, type (number of cores), and model. This information is used to look up the PVU value in the IBM PVU table.

Calculate the PVUs for a node by using the following formula:

PVUs = number of processors on the node * processor type (core count) * pvu value

To calculate the total PVUs, sum the PVUs for all nodes.