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From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.unix.admin
Subject: Re: Problem with dump
Message-ID: <18621@cbmvax.commodore.com>
Date: 6 Feb 91 15:25:06 GMT
References: <529@mesrx.UUCP> <2528@autodesk.COM>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 32

In article <2528@autodesk.COM> stevel@Autodesk.COM (Steve Litras) writes:
> In article <529@mesrx.UUCP> bbraden@mesrx.UUCP (Bill Braden) writes:
> >  DUMP: (This should not happen)bread from /dev/rra0c [block 69872]:
> >count=8192, got=-1
> 
> We've had this problem too. In fact we just replaced the disk, so I don't know
> how it will help (I'm assuming it will fix it, but you never know). According
> to our Sun engineer, it's is a fairly harmless problem (soft error), but I
> have had it bogus backups.

Well, there's no way it's a "soft" error, the data that dump was trying to read
isn't, and junk is written on the tape.  In some cases, it may be that the data
is "don't care"...

There seem to be several major causes for the problem.  One is an actual read
error, in wich case you should review the console and uerf output to find/fix
the problem.  Another is when a filesystem has been corrupted such that there
are pointers outside the partition in the structure.  Running fsck should find/
"fix" this sort of problem.

Another cause that has been mentioned from time to time is when a filesystem
completely fills a partition and the partition size isn't multiple of some
magic number of blocks (I forget the exact excuse).  In this case when the
partition fills, dump tries to do a multi-block read of the last chunk of
data and fails because the multi-block region crosses the partion boundry.
If the block in error corresponds to one of the last blocks in the partition,
this might be your problem.

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)