File Descriptor Limits

When using a large number of Virtual Hosts, Apache may run out of available file descriptors (sometimes called file handles) if each Virtual Host specifies different log files. The total number of file descriptors used by Apache is one for each distinct error log file, one for every other log file directive, plus 10-20 for internal use. Unix operating systems limit the number of file descriptors that may be used by a process; the limit is typically 64, and may usually be increased up to a large hard-limit.

Although Apache attempts to increase the limit as required, this may not work if:

system call.setrlimit(RLIMIT_NOFILE)

call does not function on your system (such as Solaris 2.3)In the event of problems you can:

sections, but only log to the main log files. (See

ulimit -S -n 100

If you want to log multiple virtual hosts to the same log file, you may want to split up the log files afterwards in order to run statistical analysis of the various virtual hosts. This can be accomplished in the following manner.

First, you will need to add the virtual host information to the log entries. This can be done using the

directive, and the LogFormat%v

variable. Add this to the beginning of your log format string:

LogFormat "%v %h %l %u %t \"%r\" %>s %b" vhost CustomLog logs/multiplevhostlog vhost

This will create a log file in the common log format, but with the canonical virtual host (whatever appears in the

directive) prepended to each line. (See ServerName

for more about customizing your log files.)modlogconfig

When you wish to split your log file into its component parts (one file per virtual host) you can use the program

to accomplish this. You'll find this program in the split-logfilesupport

directory of the Apache distribution.

This program, when run with the name of your vhost log file, will generate one file for each virtual host that appears in your log file. Each file will be called hostname.log

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Apache HTTP Server Version 2.4