Saving space in /export/root (was: Sharing /tmp through NFS)

[C'est le facteur fnet]

The root partition in 4.0 is NFS-mounted anyway, so the question about
whether /tmp should be NFS-mounted is irrelevant. Moreover, since the
clients' `root' partition is just a directory in the server's /export/root
file system, there is no fragmentation -- /tmp's can expand as much as
they want; well, more that they could under previous releases. But make
sure your /etc/rc cleans up the local /tmp.

Now for a space-saving tip. If more that one clients (on the same server)
run the same kernel, the default condition is to have a copy of vmunix in
each client's root partition/directory. So, for instance, if you have two
machines called A and B, you would have /export/root/A/vmunix and
/export/root/B/vmunix as two separate files. A better way to handle this
is to have a single file called /export/root/VMUNIX (on the server), and
then make /export/root/A/vmunix and /export/root/B/vmunix HARD links to
it.  When you have not two but ten machines on each server, the savings
become significant. Also, this way you can afford to keep a generic kernel
and a copy of kadb for each machine, without occupying any more space
(well, a few bytes for the additional directory entry!). As an added
benefit, if you modify the kernel, you only have to copy it once to
/export/root/VMUNIX and it's automagically changed for all the clients.

In our case, I have a VMUNIX.DL5060, VMUNIX.SDST60, VMUNIX.GENERIC and a
KADB in /export/root on the servers; <client>/vmunix is a hard link to the
appropriate file, and there are additional entries like
<client>/vmunix.gen and <client>/kadb on all the clients' partitions.

Conceivably, this can also be done for the /dev and the /sbin directories
easily, and for /etc with some extra work, but it's probably not worth it.

/ji