sohail@terak.UUCP (Sohail M. Hussain) (01/26/85)
We just finished upgrading from 4.1 BSD to 4.2
and I just noticed a problem with our users filesystem.
We have all our users on a ra81, and i made the file
system using "newfs ra0f ra81". That caused a file system
of size 478582 blocks to be created starting some where in
the middle of the disk, and going to the end.
After making the filesystem I did a "restore r" to read in the
old data from the 4.1 dump tapes. The did a "fsck /dev/ra0f" and
fsck complains about being "unable to read block 478580".
Futher investagation shows that blocks 478580, 478581 cannot be read.
I have tried changing the value of "fs_size" in the super block, and then
running fsck, but the 4.2 fsck is smarter than the 4.1 fsck, and it changed
the value back to the original. I also tried changed both "fs_size" and
"fs_dsize", but then fsck really complains.
So my question is how can get 4.2 to not look at those 2 blocks.
Any advice would be welcome, since the only alternative i can see is
writting out to tape, rebuilding the partition, and reading back again.
Since with tu80 drives this would take about 9-10 hours, (on a weekend too)
I would like to avoid doing that.
Thanks in advance for you consideration.
Sohail.
--
Sohail Hussain
uucp: ...{decvax,hao,ihnp4,seismo}!noao!terak!sohail
phone: 602 998 4800
us mail: Terak Corporation, 14151 N 76th street, Scottsdale, AZ 85260bill@ur-cvsvax.UUCP (Bill Vaughn) (02/18/85)
> We just finished upgrading from 4.1 BSD to 4.2 > and I just noticed a problem with our users filesystem. > We have all our users on a ra81, and i made the file > system using "newfs ra0f ra81". That caused a file system > of size 478582 blocks to be created starting some where in > the middle of the disk, and going to the end. > > After making the filesystem I did a "restore r" to read in the > old data from the 4.1 dump tapes. The did a "fsck /dev/ra0f" and > fsck complains about being "unable to read block 478580". > > Futher investagation shows that blocks 478580, 478581 cannot be read. > > I have tried changing the value of "fs_size" in the super block, and then > running fsck, but the 4.2 fsck is smarter than the 4.1 fsck, and it changed > the value back to the original. I also tried changed both "fs_size" and > "fs_dsize", but then fsck really complains. > > So my question is how can get 4.2 to not look at those 2 blocks. > > Any advice would be welcome, since the only alternative i can see is > writting out to tape, rebuilding the partition, and reading back again. > Since with tu80 drives this would take about 9-10 hours, (on a weekend too) > I would like to avoid doing that. > Take a look at the badsect(8) command. Once you've pinned down the sector numbers, badsect(8) allows you to communicate the facts to fsck(8). You can't fix bad blocks which occur in the swap area or the i-list of a file system. In that case you'll just have to rearange your file systems. Also be aware that HARD bad block errors occur spontaneously on RA's, ( and sometimes recover too). It's good to have a program that every week or so reads all the blocks of a file system and reports blocks it can't read. This should be done for all file systems and the swap area too. Sometimes the system will do this before you can get to it. Just record the block, dismount the filesystem, run badsect(8) and fsck(8) and remount the system. (Of course, the system has to be shutdown and rebooted if this happens on the root filesystem or any active filesystem). Bill Vaughn UNIV. OF ROCHESTER Center for Visual Science {allegra,seismo,decvax}!rochester!ur-cvsvax!bill