Files hidden by NFS mounts

[William Walker]

In article <1990Dec6.223032.18061 at unicorn.cc.wwu.edu>, n8743196 at unicorn.cc.wwu.edu (Jeff Wandling) writes:
> ir at cel.co.uk (ian reid) writes:
> >Suppose you have a local directory on local machine /usr/me, and that this
> >directory has files in it.  Now what happens to these files if /usr/me
> >is used as a mount point for a remote file system.
> 
> On the RS-6000 model 520 we had, it worked the way you described. Files
> that were in directory /usr/me remained there. This is something I'd
> expect on other machines. Again, any comment?

this happens on both NFS and hfs mounts.

on NFS, it is handy for keeping "necessary" files.  here at prc, we remote
mount the binaries for X11 from a spare uVax fileserver to the HP's.
so to install X safely, i can make /usr/bin/X11, copy xterm and xdm into it,
and then mount the NFS prcmvii:/usr/prc/X11/usr.bin-HP-7.0 on /usr/bin/X11.
if i lose a fileserver, xterm and xdm will still be available for my
xterminal-only users.

on hfs this is especially handy for keeping generics handy on machines where
the root passwd is considered "public" to developers without much SA
knowledge.  it is handy to keep an occasional backup of printcap, 
passwd, group, or any other file you may need.  if the machine gets royally
hosed, you can umount a file system, and copy the generic into place.
doesn't hurt to keep a spare kernel or restore binary around if you have the
space on the root partition.  ever had anyone remove /genvmunix??  it can
happen!

bill.