[comp.unix.aux] Some notes on problems in A/UX

hugh@hoptoad.uucp (Hugh Daniel) (08/17/88)

> liam@cs.qmc.ac.uk (William Roberts) wrote:

  Haveing fixed some of the bugs that liam@cs.qmc.ac.uk pointed out in 
his bugreport months ago, I guess it would be better to post them to this
group insted of just hopeing things are better next time round.

> 3. FSCK Problem
	This is a problem with the boot scripts, the program /bin/pname
	is not getting run before non root files systems are fsck'ed.
	To fix, put a line like "/bin/paname -a" in /etc/bcheckrc near
	the begining.  Then commment out the old "pname -a" in brc (You
	don't have to do this, all it will do is give some strange useless
	error messages).

> 4. /etc/NETADDRS has no apparent effect
	This file seems to be used by the software that deals with the
	ehter card.  If you get this IP adderss out of sync with the
	*REAL* one in /etc/hosts then you will have a broken network
	after the next boot.

> 1. "sync" and "powerdown" do not fully sync the disk?
	This is a standard system five problem ("Considder it Sub...").
	What I now do for ALL non crash reboots is to become root, do
	a "sync;sync;umount -a" then a "sync;powerdown" or reboot.  This
	will do a good job of saveing the non root filesystems from 
	damage, but the root is still fryed on reboot much of the time.
	(Question: Has anyone else run into cases where fsck finds a 
	problem, reboots, then finds ANOTHER problem so bad it has to
	reboot a second time?  I have seen this in A/UX and never 
	elsewhere.)

> 1. dumpfs missing from our 80 Meg disk
	Also restore, rdump, rrestore and rmt, all of which would be
	usefull at our site.  As things stand now since I have to work
	hard to backup my A/UX box I never put hard work that I would
	not want to lose on my A/UX system.  Everything lives on a Sun,
	this also gets around the problem of 14 or less character file
	names.

                ||ugh Daniel
hugh@toad.com                   Grasshopper Group,  415/668-5998
hugh@well.uucp                  212 Clayton St. San Francisco CA94117

jtkohl@athena.mit.edu (John T Kohl) (08/17/88)

In article <5123@hoptoad.uucp> hugh@hoptoad.uucp (Hugh Daniel) writes:
> ...
>	(Question: Has anyone else run into cases where fsck finds a 
>	problem, reboots, then finds ANOTHER problem so bad it has to
>	reboot a second time?  I have seen this in A/UX and never 
>	elsewhere.)
> ...

Yes.  We see this very often here at Project Athena, with the BSD
filesystem.  If /etc/passwd gets corrupted in some fashion (say, a bad
link count), fsck will happily re-set it and cause a reboot.  But since
fsck uses /etc/passwd to display owner names of broken files, the kernel
will update the inode when fsck closes the file.

So fsck has absolutely no chance of ever fixing this problem; each
reboot turns up the same problem.  Manual intervention is needed.

John Kohl <jtkohl@ATHENA.MIT.EDU>
Digital Equipment Corporation/MIT Project Athena
(As usual, the opinions expressed above do not necessarily reflect the
opinions of my employer. :-)

pokey@well.UUCP (Jef Poskanzer) (08/18/88)

In the referenced message, hugh@hoptoad.uucp (|-|ugh Daniel) wrote:
}	(Question: Has anyone else run into cases where fsck finds a 
}	problem, reboots, then finds ANOTHER problem so bad it has to
}	reboot a second time?  I have seen this in A/UX and never 
}	elsewhere.)

When I was using pre-release A/UX, I would typically reboot once or twice
a day.  fsck would find and fix a problem about on about half of these
reboots.  Maybe once in two weeks, it would do a double reboot as you
describe above.  And twice in N months, it went into continuous reboots.
fsck would claim to have fixed the problem, reboot, and then do exactly
the same thing again.  When I showed this to a wizard he mumbled something
about fsck not flushing all its buffers -- sounds pretty dangerous to me!

Anyway, I haven't used A/UX since it was released, and I assumed all these
problems were fixed.  Apparently not.
---
Jef

             Jef Poskanzer   jef@rtsg.ee.lbl.gov   ...well!pokey
          It's hard to see the forest when you're one of the trees.

karish@denali.stanford.edu (Chuck Karish) (08/18/88)

In article <5123@hoptoad.uucp> hugh@hoptoad.uucp (Hugh Daniel) writes:
>	(Question: Has anyone else run into cases where fsck finds a 
>	problem, reboots, then finds ANOTHER problem so bad it has to
>	reboot a second time?  I have seen this in A/UX and never 
>	elsewhere.)

I've seen this happen on an old version of AIX (IBM's port of System 5
rel. 2).  The third fsck found no errors.

Chuck Karish	ARPA:	karish@denali.stanford.edu
		BITNET:	karish%denali@forsythe.stanford.edu
		UUCP:	{decvax,hplabs!hpda}!mindcrf!karish
		USPS:	1825 California St. #5   Mountain View, CA 94041

jr@oglvee.UUCP (Jim Rosenberg) (08/23/88)

From article <6836@well.UUCP>, by pokey@well.UUCP (Jef Poskanzer):
> When I was using pre-release A/UX, I would typically reboot once or twice
> a day.  fsck would find and fix a problem about on about half of these
> reboots.  Maybe once in two weeks, it would do a double reboot as you
> describe above.  And twice in N months, it went into continuous reboots.
> fsck would claim to have fixed the problem, reboot, and then do exactly
> the same thing again.  When I showed this to a wizard he mumbled something
> about fsck not flushing all its buffers -- sounds pretty dangerous to me!

I probably shouldn't stick my nose into this, since I don't have a Mac II and
don't run A/UX.  But it seems to me that the better part of wisdom in dealing
with fsck is to know how to boot a "lifeboat" UNIX system from a floppy, and
fsck your "raw" hard disk root file system while it's *UNMOUNTED*.  This would
allow any number of passes through fsck without any auto reboots.

Unfortunately, there are more versions of UNIX on personal computers than you
can shake a stick at that *DON'T TELL YOU* how to create a bootable floppy.
If your A/UX documentation doesn't tell you how to run fsck with your hard
disk off-line when working with a bootable floppy, scream like hell.  There
are cases where booting the floppy is the only safe thing to do, unless you
simply decide to bite the big one and restore the whole damn disk from
floppies.
-- 
Jim Rosenberg                        pitt
Oglevee Computer Systems                 >--!amanue!oglvee!jr
151 Oglevee Lane                      cgh
Connellsville, PA 15425                                #include <disclaimer.h>

dwb@Apple.COM (David W. Berry) (08/25/88)

In article <271@oglvee.UUCP> jr@oglvee.UUCP (Jim Rosenberg) writes:
>From article <6836@well.UUCP>, by pokey@well.UUCP (Jef Poskanzer):
>> When I was using pre-release A/UX, I would typically reboot once or twice
>> a day.  fsck would find and fix a problem about on about half of these
>> reboots.  Maybe once in two weeks, it would do a double reboot as you
>> describe above.  And twice in N months, it went into continuous reboots.
>> fsck would claim to have fixed the problem, reboot, and then do exactly
>> the same thing again.  When I showed this to a wizard he mumbled something
>> about fsck not flushing all its buffers -- sounds pretty dangerous to me!
>
>I probably shouldn't stick my nose into this, since I don't have a Mac II and
>don't run A/UX.  But it seems to me that the better part of wisdom in dealing
>with fsck is to know how to boot a "lifeboat" UNIX system from a floppy, and
>fsck your "raw" hard disk root file system while it's *UNMOUNTED*.  This would
>allow any number of passes through fsck without any auto reboots.
	Well, on A/UX it's pretty simple.  You boot the Mac OS, run sash
and instead of launching unix, you run the standalone fsck.  The standalone
environment allows you to run many of the common utilities (dd, cp, mv, rm,
ed, fsck, fsdb, and more)  It's not a bootable floppy based unix, but it
does solve most of the problems.
>-- 
>Jim Rosenberg                        pitt
>Oglevee Computer Systems                 >--!amanue!oglvee!jr
>151 Oglevee Lane                      cgh
>Connellsville, PA 15425                                #include <disclaimer.h>




Opinions:  MINE, ALL MINE! (greedy evil chuckle)

David W. Berry
apple!dwb@sun.com	dwb@apple.com	973-5168@408.MaBell