/tmp and /usr/tmp

[rcd at opus.UUCP]

<>
The split between /tmp and /usr/tmp is in the same spirit as the split
between /bin and /usr/bin.  Essentially, you may have some small, fast
disks and some larger, slower ones - so you put the more important but
smaller stuff in /tmp.  Depending on the state of your manual pages,
hier(7) will at least suggest this answer.  I don't know of anyplace where
it is stated that /tmp and /usr/tmp differ in "permanence" - and I would
suggest that it would be very unwise to count on anything in either place
lasting beyond one terminal session (i.e., remaining after you log out).

It's hard to give even a ballpark guide to how big a file can get before it
should be put in /usr/tmp rather than /tmp, but I'll submit (at the risk of
getting flamed mercilessly) that if it's under 10Kb, /tmp is fine; if it's
over a couple hundred Kb it better be in /usr/tmp.  The consequences of
running out of space in /tmp are sufficiently unpleasant not to betaken
lightly.

If you have only one chunk of disk for temporary storage, try to arrange so
that you still have both /tmp and /usr/tmp, to avoid breaking programs you
may receive.  (This can be messy - if you don't have symbolic links, it
means that /tmp and /usr/tmp have to be in the same filesystem, which
leaves you with all of /usr in /.)
-- 
{hao,ucbvax,allegra}!nbires!rcd