init's untimely death.

[Ed Hew]

I had originally replied to this via email, however it occurs to me
that perhaps someone else may have similar problems, or better yet,
have resolved them.

In article <1989Jun21.114506.1378 at tapa.uucp> larry at tapa.uucp (Larry Pajakowski) writes:

> Perhaps someone can shed some light on a perplexing problem we are having.
> We have a Compaq 386/20 running Xenix-386 2.3.1 with Excelan TCP/IP V3.5
> and Xenix-Net 1.2.

I was in a similar (lack of) light several months ago, (shortly after our
conversion to 2.3.1).  The major difference was that it wasn't TCP/IP,
it was uucp (kind of) causing me headaches.
> 
> About once a week more or less init dies.  After that of course the machine
> slowly grinds to a halt and must be powered off.  I now have a script running
> periodically which checks for init and reboots after doing a ps if there is no
> init.  Ok that keeps it alive but why?

My scenario was as follows:

I'd leave this system just humming along and go to work.  I'd return
late that night and find my system ground to a halt.  Nobody was cleaning
up defunct processes and my process table was full.  Hence the system was
effectively dead.  init had somehow been assasinated.

Of course, I'd discover this after I logged on with my *non*root account,
so I couldn't even do a proper shutdown.  With no init, I have no getty,
and can get no login.  I'd log on on tty01; the original getty would at least
let me do that and replace itself with my login shell, but, then.... log off
to log on as root, and...  well......  [arghhh!  where's that switch?
  ....sure like fsck, ummhmmmmm].

RTFM says something like:  "shutdown can only be run in the foreground by
root".

After a couple of weeks of fruitless testing and surmization (sp?), I turned
the process accounting on.  Well, let's be honest, I always had the proc
accounting on, I just decided to look at it.  1/2 :-)

Sure enough, init was exiting for some reason right when I had a cron task
disable and enable the tty that had an attached uuxqt happening, processing
news.

Some background is required here.  The disable/enable was a workaround to
a problem whereby DTR wasn't (for some still unresolved reason) being raised
after polling our host for news.  So, we simply cron'd a script to disable/
enable the TBit tty every 15 minutes if nobody was on it at the time.
That solved the (no DTR) problem, but then the above occured.  The disable/
enable was assassinating init.  Process accounting says so.

Now we check to make sure uuxqt isn't running at that time as well.
Haven't had a problem since.

I can also tell you that the above results have been manually recreated
on this site.  Sometimes.  It's not consistent.  Arghhhh!
There is a missing factor here.  I don't know what it is.

> I've talked both to SCO and Excelan.  Neither has been able to help much.
> It may be slightly worse under heavy TCP/IP load but then I've had it happen
> on an idle machine.  There have been power line glitch monitors on the power
> and we have run diagnostics over a weekend with no indications of any problem.
> The only other clue is 2 kernel panics over the last 3 months "Free inode
> isnt't".

In my case:  A thought:  I wonder if this could be related to the old
problem in pre-2.2.x releases where the docs warned us that using a
disable/enable sequence without separating them by at least a 1 minute
interval was asking for trouble.

All I can suggest is that you check out the above info; check out what
your process accounting tells you.  Find out what's happening when init
dies, and prevent it from happening.

If you ever find out *why* this happens, please email me.  Right now I am
still using a workaround.  I'd rather find a *fix*.

> I would appreciate hearing from anyone with some ideas either by email or
> phone.  Many Thanks.

Hope this helps.
> 
> Larry Pajakowski > Abbott Labs.  ...!ddsw1!abtcser!larry 1-312-937-1153

		--ed		{edhew at egvideo.uucp}

  Ed. A. Hew     Authorized SCO Technical Trainer      Xeni/Con Corporation
  work:  edhew at xenicon.uucp	 -or-	 ..!{uunet!}utai!lsuc!xenicon!edhew
  home:	 edhew at egvideo.uucp	 -or-	   ..!{uunet!}watmath!egvideo!edhew
  # I haven't lost my mind, it's backed up on floppy around here somewhere!