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From: lnz@edsel.UUCP (Leonard Zubkoff)
Newsgroups: comp.sys.apollo
Subject: Updating Large Rings
Message-ID: <8710122247.AA01482@rainbow-warrior.lucid.com>
Date: Mon, 12-Oct-87 18:47:21 EDT
Article-I.D.: rainbow-.8710122247.AA01482
Posted: Mon Oct 12 18:47:21 1987
Date-Received: Wed, 14-Oct-87 05:12:48 EDT
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   Date: 1 Oct 87 18:01:00 GMT
   From: navajo!apollo!bares@eddie.mit.edu  (Vittorio Bares)
   Organization: Apollo Computer, Chelmsford, Mass.
   Sender: navajo!apollo-request@YALE.ARPA

   [referring to Leonard Zubkoff's installation scheme...]

   This installation scheme is fine but only under certain controlled
   conditions. For instance, presently, the only way to preserve a subsystem
   manager stamp on an object from magnetic tape using RBAK is to include the
   -SACL option for each restore. If you are restoring a network which is 
   'open' (i.e. does not use registries or does not protect its files using
   acl's.) then this would not be a problem. Otherwise, the node being restored
   would inherit all the acl's presently on the tape. If your network is one in
   which each developer or group has their own protections for their disks then
   you would surely receive complaints from people having to re-acl their nodes
   each time a restore was done. With CPT you are safe in this respect, because
   CPT carries subsystem stamps over to the new destination automatically by
   default.

Exactly.  I decided that the reduced maintenance overhead in our environment
would be worth the trouble of enforcing uniformity.  While individual groups
keep their own directories protected as they please, I install the system
software with secure system acls.  We let anyone know a root password who needs
it, but I strongly encourage them not to mung the system software.  The RBAK
command indeed does use -sacl and -pdt.  I left most of the exact details of
the procedure out, preferring instead to explain the basic idea.  I'll happily
mail out an example if anyone requests it.

A more obnoxious problem was that the local registry must be recreated.

   Secondly, what happens if there are links on the node you are restoring that 
   point to another volume ? RBAK and CPT will both copy through the link,
   possibly causing another node to now contain inconsistent software, which
   could result in crashing that node.

I normally do this particular restore procedure to virgin disks, as a way of
loading up the system software cheaply.  In the past, most of our machines had
only small disks and so only system software and paging space came from the
local disk; with larger disks that people use for user software, I haven't yet
decided the best procedure.

   Thirdly, what happens to template files which have been customized by the node
   owner ? Do you have a scheme that assists the user in protecting their
   customized files from getting overwritten by the standard template files ?

Actually, we do not allow node owners to customize the startup scripts.
Rather, for anything except for starting up system servers, the login startup
scripts expect the user's login script to create the initial shell.  The system
software is uniform; the user side is not.  The few node specific files in
`node_data (thishost, networks, siomonit_file (if present) and startup_sio.sh
(if present)) are saved away and restored at the end of the procedure.

   As stated earlier, the scheme outlined by Leonard Zubkoff, is undoubtedly 
   quicker than the standard Apollo scripts but, there is no such thing as a
   free lunch :-), this scheme may not be applicable to all Apollo networks.

I concur.  It took several tries to make this whole process work, but it does
have advantages when it is applicable.  For example, the same technology allows
me to dump the system software from a standalone machine so that I can restore
it without the normal installation, and without needing an apollo bootable
cartridge tape (I make my own as part of the dump).  I used this when I knew I
would be having a disk replaced on a standalone nodem and again at the AAAI
show to clone a copy of an environment onto a node we would be demonstrating
on.

   Cheers,

       Vittorio Bares
       bares@apollo.UUCP