Apache Reference: http_core, MaxSpareServers

MaxSpareServers

Maximum Number of Idle Server Child Processes
Syntax: MaxSpareServers A
Example: MaxSpareServers 15
Since: Apache 1.0

This directive sets the maximum number of idle server child processes. An idle process is one that is not currently handling a request. If more than number processes are idle, then the parent process will kill off the excess processes.