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Stefano
Asked: 2011-06-07 09:00:05 +0800 CST

What 'LockFile' is for in Apache2?

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From apache2 doc:

The LockFile directive sets the path to the lockfile used when Apache is used with an AcceptMutex value of either fcntl or flock.

And about AcceptMutex

The AcceptMutex directives sets the method that Apache uses to serialize multiple children accepting requests on network sockets.

I am running apache 2.2 with mod_wsgi for a django website on an Ubuntu 64bit box.

what is it for? is this even ever used?

I can't find a file in the specified location.

My /usr/sbin/apache2 -V tells me: 

-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE

which should mean that sysvsem is used. Does that mean that LockFile is not used?

apache-2.2

1 Answers

  1. Best Answer

    http://httpd.apache.org/docs/2.0/mod/mpm_common.html#lockfile says: 

    The LockFile directive sets the path to the lockfile used when Apache

    is used with an AcceptMutex value of either fcntl or flock. This directive should normally be left at its default value. The main reason for changing it is if the logs directory is NFS mounted, since the lockfile must be stored on a local disk. The PID of the main server process is automatically appended to the filename.

    Brief version: do not touch, unless the file would end up on an NFS-mounted files ystem.

    If you do not find the file where you expect/set it to be, it may mean, that AcceptMutex isn't set to neither fcnl nor flock. This may be optimal or not, depending on your architecture, as documented here: http://httpd.apache.org/docs/2.0/misc/perf-tuning.html.

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