Apache Reference: http_core, MinSpareServers
Minimum Number of Idle Server Child Processes
Syntax: MinSpareServers A
Example: MinSpareServers 10
Since: Apache 1.0
This directive sets the minimum number of idle server child
processes. An idle process is one that is not currently handling
a request. If fewer than number processes are idle, then the
parent process creates new children at a maximum rate of one per
second.