From: COUPRIE Kees (Kees.COUPRIE@swift.com)
Date: Tue Aug 31 2004 - 03:23:05 EDT
All,
Thanks to all who replied. Here's a summary of the suggestions I got.
First the responses that did not help.
* "Possibly somebody has threaded some mount commands in one of the
/sbin/rc*.d/S* scripts."
- "No mount commands are present in scripts where they should not be.
Besides, when booting up in single user mode, the /sbin/rc*.d/S*
scripts are not even used."
* "Did the operators REALLY follow the instructions?"
- "Well, they claim they did, but I have not tortured them yet."
* "Perhaps there's a mount command in /etc/profile."
- "No"
* "When booting a system into single user mode, the sysinit entries
in /etc/inittab are used. Perhaps there's a sysinit entry that
mounts the file systems."
- "Interesting, but no. Nothing unusual in the inittabs"
Now here's the response that solved the mystery.
Received from Steve Hamilton:
* "When you boot up the system in single user mode, the /etc/mnttab
file is not cleared like it is during a normal system boot.
Because of this, the 'mount' command will read the existing
/etc/mnttab file and display what it shows, which was the mount
table from when the system was up and running before you booted
into single user mode...
To get 'mount' to correctly display the actual filesystems mount
in single user mode, you will need to do:
# mv /etc/mnttab /etc/mnttab.old
# mount
Now, you should see the appropriate information..."
A little investigation showed that Steve is absolutely right. We also
discovered that /etc/mnttab is not the only file not being cleared. E.g.
/etc/utmp is also not cleared, so even with the system in single user
mode, the /usr/bin/who command (after mounting /usr) even showed users
that logged in before the system was brought down.
Again, thanks for all your replies.
Kees Couprie
> ----- Original Message -----
> > I stumbled across a weird problem. On several systems we
> > had to extend
> > /var, and I created change requests to do so.
> >
> > In the instructions I had the operators reboot the system
> in single user
> > mode (not just init s, but shutdown the system and boot it
> using ISL and
> > then do hpux -is).
> >
> > Now the weird thing is that on some systems this worked
> perfectly, but
> > on some other systems, when the operator tried to do the
> extendfs (after
> > lvextend), the system refused to do this because /var was
> mounted. In
> > fact ALL file systems in /etc/fstab were mounted.
> >
> > I have tried to figure out what exactly happened and for as
> far as I can
> > see (from rc.log and the audit files) the instructions were
> executed as
> > prescribed, but still all file systems were mounted.
> >
> > I have been discussing this with my fellow sysadmins and we
> all agree
> > that this is theoretically impossible, but it happened anyway.
> >
> > Any idea how these file systems could have been mounted
> when the system
> > was brought up in single user mode?
> >
> > Rgrds,
> > Kees Couprie
> >
--
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