Apache: The Definitive Guide, 3rd Edition

Name

SSLMutex

Synopsis

SSLMutex type
Default: none BUT SEE WARNING BELOW!
Server config
Apache v2 only

This configures the SSL engine’s semaphore — i.e., a multiuser lock — which is used to synchronize operations between the preforked Apache server processes. This directive can only be used in the global server context.

The following mutex types are available:

none

This is the default where no mutex is used at all. Because the mutex is mainly used for synchronizing write access to the SSL session cache, the result of not having a mutex will probably be a corrupt session cache . . . which would be bad, and we do not recommend it.

file:/ path / to / mutex

Use this to configure a real mutex file by defining the path and name. Always use a local disk filesystem for /path/to/mutex and never a file residing on a NFS- or AFS-filesystem. The Process ID (PID) of the Apache parent process is automatically appended to /path/to/mutex to make it unique, so you don’t have to worry about conflicts yourself. Notice that this type of mutex is not available in Win32.

sem

A semaphore mutex is available under SysV Unices and must be used in Win32.

Example

SSLMutex file:/usr/local/apache/logs/ssl_mutex