Mailing List Archive: the meaning of /var

> > /var is for files that are specific to the system they are on.
> Can you provide a reference for this somewhat extraordinary claim?

From the Solaris filesystem man page: ``/var: Root of a subtree for
varying files. Varying files are files that are unique to a machine but
that can grow to an arbitrary (that is, variable) size.''

/ and /etc are also host-specific, but they're on the root disk, which
is usually very small. Sun needed a host-specific place for mailboxes,
log files, etc., so they invented /var.

It turned out that making a new name for non-shared files was a mistake:
Sun should have left /usr alone, and set up a new name for shared files,
so that programs with host-specific files in /usr would continue to
work. Fortunately they did /usr/share and /usr/kvm the right way.

---Dan
Let your users manage their own mailing lists. http://pobox.com/~djb/qmail.html

On 23 Feb 1997, D. J. Bernstein wrote:

> >From the Solaris filesystem man page: ``/var: Root of a subtree for
> varying files. Varying files are files that are unique to a machine but
^^^^^^^
> that can grow to an arbitrary (that is, variable) size.''
>
[...]
> It turned out that making a new name for non-shared files was a mistake:
> Sun should have left /usr alone, and set up a new name for shared files,
> so that programs with host-specific files in /usr would continue to
> work. Fortunately they did /usr/share and /usr/kvm the right way.

IMHO, the basic difference between /usr and /var is: /usr is almost
immutable (and you can mount it read-only) but /var is changing very
often (you cannot mount it read-only); such a distiction is very
important--for instance for back-ups or system integrity checks (tripwire)

executables and man pages of any kind fall into the first category (almost
immutable files), and this is why they should not stay in /var

--Pavel Kankovsky aka Peak (troja.mff.cuni.cz network administration)