Role of processor value units in assessing licensing requirements

You can obtain information about the use of processor value units (PVUs) by server devices. You can also obtain information about the number of client and server devices that are managed by Tivoli® Storage Manager. Use the data that you collect to assess the licensing requirements for the Tivoli Storage Manager system.

Important: The PVU calculations that are provided by Tivoli Storage Manager are considered estimates and are not legally binding. The PVU information reported by Tivoli Storage Manager is not considered an acceptable substitute for the IBM® License Metric Tool.

PVU estimation process

The following figure illustrates the PVU estimation process.

The image is a graphical depiction that illustrates how PVU information is collected.

Review the following process to understand how Tivoli Storage Manager estimates PVUs.
  1. When you install Tivoli Storage Manager, 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 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 estimates 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 classifying devices, see Device classification.
    Restrictions:
    • A client node can send Common Inventory Technology information to the server only if a V6.3 or later backup-archive client is installed on the client node.
    • Common Inventory Technology is not installed automatically on client nodes that are running on Linux operating systems. To obtain PVU information from a client node that is running on a Linux operating system, you must install Common Inventory Technology on the client node. For instructions, see Installing the Tivoli Storage Manager backup-archive clients.
  3. The server stores the Common Inventory Technology 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. The estimates are also based on the 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 server installation.

You can browse PVU information by issuing commands that provide PVU estimates. For instructions about obtaining and adjusting PVU estimates, see Estimating processor value units.

Device classification

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 operating system 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.

When you assign a classification, consider the services that are associated with the device. For example, a notebook computer might be a client device if it is distributed to a university staff member as a single-use workstation. The same computer might be a server device if it is distributed to a department administrator, who provides more services. The department administrator might provide services such as sharing files on the computer to multiple workstations.

In a Tivoli Storage Manager system, you can assign multiple client node names to the same physical workstation. For example, a clustering solution can have several node names that are defined in the server environment to provide protection if a failover occurs. Redundant node names, or node names that manage data for physical workstations that no longer exist, must not be counted for licensing purposes. In this case, you might classify the node as other by using the UPDATE NODE command.

Limitations

The PVU calculations are estimates because the software cannot determine all 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 or later server devices that are connected with the Tivoli Storage Manager server since the installation of or upgrade to Tivoli Storage Manager V6.3 or later.
  • 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.

Formula for PVU estimation

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.

Related information

Table 1. Information about PVUs and licensing
Information type Location
IBM PVU table ftp://public.dhe.ibm.com/software/tivoli_support/misc/CandO/PVUTable/
PVU calculator https://www.ibm.com/software/howtobuy/passportadvantage/valueunitcalculator/vucalc.wss
PVU frequently asked questions http://www.ibm.com/software/passportadvantage/pvufaqgen.html
PVU licensing for distributed software http://www.ibm.com/software/passportadvantage/pvu_licensing_for_customers.html
PVU terminology http://www.ibm.com/software/passportadvantage/pvu_terminology_for_customers.html