The /var Hierarchy

/var contains:

• account
• cache
• crash
• cron
• games
• lock
• log
• mail
• opt
• run
• spool
• state
• tmp
• yp

There are also some directories which are reserved for use by the sysop, or by old software which dosn't comply with the FHS (yet).

• backups
• local
• msgs
• preserve

A brief introduction to the subdirectories.

account

The current process accounting logs. (if supported).

cache

Cache directories, ie fonts, man, www, etc.

crash

This is where the system crash dumps should be written. (if supported).

cron

Under linux /var/cron used to be /var/spool/cron. It has been moved out of /var/spool to fit the definition of /var/spool better. /var/spool was chosen due to precedent in BSD UNIX.

games

Variable game data (ie levels, high scores, etc).

lock

Hopefully all lock files will soon be in the one place. There is also a standard format for lock files defined. (the HDB UUCP lock file format).

log

Most logs should be written to this directory or an appropriate subdirectory.

opt

Variable data should be installed in /var/opt/<package>, where <package> is the name of the subtree in /opt where the add-on package is installed. Some variable data may be installed under /etc.

run

This directory contains system information files describing the system since it was booted. This directory should be emptied every reboot. PID files, once put in /etc, should now be put here. There is a standard for the PID files specified, and a few other files should be in here as well. See the standard for more details.

spool

Spool directories.

state

Variable state information. This directory is used to preserve the state of an application between invocations, and instances. It should remain valid after a reboot, and should not contain logging, or spooled data. Packaging systems (ie rpm, dselect) will be using subdirectories under /var/state to maintain package data.

tmp

Used for storing temporary data which needs to be preserved between reboots. Data to be deleted in a site-specific manner.

yp

Variable data for NIS. NIS+ should use /var/nis instead.

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