SUMMARY: Bad Block Management

From: Jared Perkins (
Date: Thu Mar 19 1998 - 11:49:23 CST


Thank you very much to:

Sean Ward
Aaron Lafferty
Birger Wathne
D. Stewart McLeod
Charlie Mengler

for your quick reply.

I'm assuming the raid controller fixed the problem itself, and that it was
simply reporting the problem to me after the fact. All your comments were
very helpful.

Jared Perkins
Graphic Color Service

Sean Ward wrote:

Hi Jared. With SCSI disks, all bad block management is handled by the
on-board SCSI controller on each disk. The only thing you can do is run a
bunch of tests under the analyze menu in format and hope the controller
figures out about the bad block.

Aaron Lafferty wrote:

Yes, add it to the defect list, though depending on the RAID controller
this may be taken care of in its hardware. Watch that disk carefully
for awhile and make sure you have a spare. Bad blocks aren't something
you should see as most drives have enough spare blocks that hotfix when
they detect a block going bad that seeing a bad block appear is usually
not a good thing.

Birger Wathne wrote:

Modern SCSI disks usually handle defects internally. So if you see
a message about a bad block it's time to get a new disk.


D. Stewart McLeod wrote:

Just do the format analysis read and then make sure that you do a fsck
afterwards. The fsck will notify you if any files got wiped away from
the bad blocks - those will need to be restored from backups.


Charlie Mengler wrote:

Format may not be necessary.
In some cases the mapping of a bad block on to the
bad block list is "automatic" once any file that
contains the bad block is deleted.

Of course this "soultion" presents a new problem.
How do you identify which file needs to be moved
in order to get the bad block mapping to occur.

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