Configuring the Worker MPM

StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 MaxRequestsPerChild 0

The Worker MPM is an Apache 2 MPM that allows you to combine processes and threads. You can specify the number of processes that will be created at startup by using the StartServers directive, as with the Prefork MPM. Each of the processes will have several threads; how many each will have is specified by the THReadsPerChild directive. The number of threads in each process is fixed, but processes are created or destroyed to maintain the total number of threads between specified limits. Those limits can be configured using MinSpareThreads and MaxSpareThreads. These directives are the counterparts of the MaxSpareServers and MinSpareServers directives in process-based servers.

Apache monitors the total number of threads across all processes and creates or destroys processes accordingly. As in Prefork, MaxClients specifies the maximum number of processes. In the Worker MPM, each process has several threads in turn, so the maximum number of simultaneous clients is MaxClients times the setting of ThreadsPerChild. MaxThreadsPerChild specifies the maximum number of threads per process and can be changed between restarts. THReadLimit specifies an upper limit that cannot be changed between restarts. The StartServers and MaxClients directives are identical to the ones described in the section named "Configuring the Prefork MPM."