Cisco Unity

Cisco Personal Communications Assistant Scalability

Document ID: 69299

Updated: Jul 28, 2008



Cisco Personal Communications Assistant (Cisco PCA or CPCA) implements a throttling mechanism to control the load that browser requests put on the Cisco Unity server. The throttling mechanism returns a "Server is busy" message to users when the server begins to overload. A set of parameters defined in a configuration file controls the throttling. If you change the values of these parameters to allow more load on the server, the result is more users that are able to concurrently use the system without getting the "Server is busy" message. However, more load from web traffic implies that the server might not have enough capacity left to process voicemail traffic.

The parameters are initially set to the same value regardless of the hardware platform due to a limitation of the Cisco Unity installation program. The values set by the installer are appropriate for the low-end platforms but too stringent for high-end platforms, which can handle more load. This means that high-end platforms do not scale to their full potential out of the box. This document provides instructions on how to change the parameters to their optimum values on high-end platforms. The values for these throttle parameters were selected carefully. Use only the value appropriate to your platform as indicated in the procedure in this document. Also note that if you upgrade Cisco Unity or re-run Cisco Unity setup to change features, it might reset the parameters to the default values. In this case, you need to repeat this procedure.

Note: Ensure that Cisco Unity is properly installed and works before you use the information in this document.



There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

Do not use the information in this document on servers or software releases other than the ones in this section. This action can destabilize your Cisco Unity setup, and Cisco does not support it.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to Cisco Technical Tips Conventions for more information on document conventions.

Change Cisco PCA Throttle Parameters

The throttle parameters are in an XML file. For platform overlay numbers 2 and 3, you must edit the file and restart the web server on Cisco Unity to change the parameters. For platform overlay number 1, you can skip this procedure, as the default throttle parameter value allows for the supported load for this platform.

Note: Access to Cisco PCA is disrupted while the web server restarts.

Complete these steps:

  1. Find the <commserver>\cscoserv\ciscopca\WEB-INF\ directory.

    The root directory of your Cisco Unity installation is <commserver>. For example, C:\commserver.

  2. Locate the file web.xml and make a copy of it.

  3. Open the file with a text editor such as Microsoft Notepad.

  4. As applicable, change the value of the max-requests setting from 3 to one of these values, based on your platform:

    Platform Overlay Number Value of max-requests setting
    1 3 (same as the default - no need to change this value)
    2 6
    3 10

  5. Save the file and close the text editor.

  6. Restart the Cisco Tomcat service from the Services MMC control panel.

  7. If failover is in use, repeat step 1 through step 6 on the secondary Cisco Unity server.

warning Warning: If you upgrade Cisco Unity or re-run Cisco Unity setup to change features, it might reset the parameters to the default values. If this happens, repeat the steps in this document.

If you accidentally change other contents of the web.xml file:

  • The Tomcat service can fail to start.

  • Cisco PCA might not be accessible after the service is restarted.

Compare the contents of the current web.xml file with the backup copy made earlier and make sure that there are no other changes if this happens.

Related Information

Updated: Jul 28, 2008
Document ID: 69299