Tuning the Service Dispatcher
Using Tools > Service Dispatcher Tuning, you can configure the parameters to improve service dispatcher performance.
The Service Dispatcher parameters are the Apache Multi-Processing Module (MPM) worker parameters. The Apache MPM Worker module implements a multi-threaded multi-process web server that allows it to serve higher number of requests with limited system resources. For more information about the Apache MPM Worker parameters, refer to https://httpd.apache.org/docs/2.2/mod/worker.html.
The following table provides information about the configurable parameters and recommendations for Service Dispatcher performance.
| Parameter | Default Value | Description |
|---|---|---|
| StartServers | 64 | The number of apache server instances that start at the beginning when you start Apache. It is recommended not to enter the StartServers value more than the value for MaxSpareThreads, as this results in processes being terminated immediately after initializing. |
| ServerLimit | 1600 | The maximum number of child processes. It is recommended to change the ServerLimit value only if the values in MaxClients and ThreadsPerChild need to be changed. |
| MinSpareThreads | 512 | The minimum number of idle threads that are available to handle requests. It is recommended to keep the MinSpareThreads value higher than the estimated requests that will come in one second. |
| MaxSpareThreads | 1600 | The maximum number of idle threads. It is recommended to reserve adequate resources to handle MaxClients. If MaxSpareThreads are insufficient, the webserver will terminate and frequently create child processes, reducing performance. |
| ThreadLimit | 512 | The upper limit of the configurable threads per child process. To avoid unused shared memory allocation, it is recommended not to set the ThreadLimit value much higher than the ThreadsPerChild value. |
| ThreadsPerChild | 288 | The number of threads created by each child process. It is recommended to keep the ThreadsPerChild value such that it can handle common load on the server. |
| MaxRequestWorkers | 40000 | The maximum number of requests that can be processed simultaneously. It is recommended to take into consideration the expected load when setting the MaxRequestWorkers values. Any connection that comes over the load, will drop, and the details can be seen in the error log. Error log file path - /var/log/apache2-service_dispatcher/errors.log |
| MaxConnectionsPerChild | 0 | The maximum number of connections that a child server process can handle in its life. If the MaxConnectionsPerChild value is reached, this process expires. It is recommended to set the MaxConnectionsPerChild value to 0, so that this process never expires. |