Fixing bad blocks (was: Re: Do you need to dismount /usr to

[Jerry McAllister]

> 
> At 01:18 PM 11/10/2004, you wrote:
> >Your problem seems to be bad blocks in the /usr file system.
> >That has nothing to do with dump.  It is a bad spot on the disk.
> >fsck will not fix that sort of thing.   If you can figure out
> >what files sit on the bad spots, you might be able to delete them
> >and then do your dump.   Then you should immediately replace the
> >disk.
> 
> I tarred up all of /usr to another filesystem, and I did see an error 
> reading a core dump file from squid. I deleted the file and I was then able 
> to dump /usr successfully. So that's good news.
> 
> However, I apparently need to fix the bad blocks before my RAID will 
> rebuild. (I had hoped it would do file-wise copies, but it looks like it 
> does lower level reading.)
> 
> It is my understanding that an IDE disk will only remap a bad block on a 
> write, not just a read. My plan is to load up /usr with enough files to 
> fill it up; this should write to the bad blocks and force them to be 
> remapped to spares.
> 
> I am hopeful that the drive is still healthy, as it only shows 2 SMART 
> errors. (Can a core dump cause a bad block or two?)

A core dump will not create bad blocks.  They are usually due to bad
spots on the disk - it is physical.   You could see if there is a
surface scan available in your bios or some accompanying diagnostic
utilities.   But, the reality is that if you start actually seeing
bad blocks reported, then there is a strong likelyhood that the disk
has already had others that were concealed by the automatic remapping
and is coming near to its demise.  So, that makes it a good time to
replace the drive rather than leaving yourself open to problems later - 
and maybe not so much later either.

So, good luck,

////jerry

> 
> (Of course, the 3ware twe driver may not allow rebuilds yet on the 7000 
> cards, so I may have to try a Knoppix CD too.)
> 
> Thanks to all for the input.
> 
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Matt Staroscik * KF6IYW * mstar at speakeasy.net * http://wrongcrowd.com
> "The combined weight of the horrors I have authored wrought would crush
> your carbon hearts into perfect diamonds of terror."
>                                          -- Leonid Kasparov Destroyovitch
> 
> 
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