Help with mvaxII/Ultrix crashing irreversibly

[George Robbins]

In article <2355 at maccs.McMaster.CA> art at maccs.UUCP (Art Mulder) writes:
> 
> 	It has been doing a good impression of a yo-yo for the past several
> months.

>   kda500: hard error, ra0a: hard error sn5886    (<- whole bunch of these)
>   start=0, len=120, fs=/usr
>   panic: allocg: map corrupted

The hard error is pretty indicative:

1) If the sector number is within the address range of the disk, then your
   disk drive is screwed up and you have to either map out the bad block
   or get a new drive.  The hard error says that it could not complete the
   operation, so it either read or wrote trash...

2) If the sector number is outside the address range of the disk, then
   you have corrupted your file structure somehow.  Normal causes are
   overlapping partitions, data structures in memory being corrupted -
   either by hardware or software or a sick disk controller.

Check all the hardware stuff again, also check for dead fans or marginal
power supplies.  Run a diagnostic on the disk drive and see if it has
trouble with that bad block.  Has a guru look at the data on the disk
to see whether something identifiable left it's spoor...

The actual panic message says something about a cylinder group map being
confused, which could point either memory corruption, or that bad disk
block being in part of the disk structure overhead rather than in a
regular data block.

I had endless grief trying to get Ultrix running on a 785, it turned out
to be a bad memory controller that gradually forgot stuff left laying in
the buffer pool for too long.  The results when you finally checked the
disk were truely ugly.

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr at uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)