Setting Up Quality of Service

To configure the quality of service settings for a server instance or a class of virtual servers, you need to configure the settings in through the user interface. To actually enforce your quality of service settings, you must also set up Server Application Functions (SAFs) in your obj.conf file.

To configure quality of service, perform the following steps

To configure quality of service

1. From the Server Manager, click the Monitor tab.

2. Click Quality of Service.

   A page appears listing general settings for quality of service, followed by a list containing the server instance and each class of virtual servers.

3. To enable quality of service the server instance, click Enable.

   By default quality of service is enabled. Enabling quality of service increases server overhead slightly.

4. Choose the Recompute Interval.

   The recompute interval is the number of milliseconds between each computation of the bandwidth for all servers, classes, and virtual servers. The default is 100 milliseconds.

5. Choose the Metric Interval.

   The metric interval is the interval in seconds during which the traffic is measured. The default value is 30 seconds. All bandwidth measured during this time is averaged to give the bytes per second.

   If your site has a lot of large file transfers, use a large value (several minutes or more) or this field. A large file transfer might take up all the allowed bandwidth for a short metric interval, and result in connections being denied if you’ve enforced the maximum bandwidth setting. Since the bandwidth is averaged by the metric interval, a longer interval smooths out spikes caused by large files.

   If the bandwidth limit is much lower than available bandwidth (for example, 1 MB-per-second bandwidth limit but with a 1 GB-per-second connection to the backbone), the metric interval must be shortened.

   Please note that if you have large static file transfers and a bandwidth limit that is much lower than available bandwidth, you have to decide which situation to tune for, because the problems require opposite solutions.

6. Enable quality of service for the server instance and/or the virtual server classes.

   The lower portion of the screen lists the server instance and server classes. Choose Enable as the action next to the items for which you want to enable quality of service.

7. Set the maximum bandwidth, in bytes per second.

8. Choose whether or not to enforce the maximum bandwidth setting.

   If you choose to enforce the maximum bandwidth, additional connections are refused, once the server reaches its bandwidth limit.

   If you do not enforce the maximum bandwidth, server logs a message to the error log, when the maximum is exceeded

9. Choose the maximum number of connections allowed.

   This number is the number of concurrent requests processed.

10. Choose whether or not to enforce the maximum connections setting.

    If you choose to enforce the maximum connections, additional connections are refused, once the server reaches its limit

11. If you do not enforce the maximum connections, when the maximum is exceeded the server logs a message to the error log.

12. Click OK.