one or more disks failling

[Wolfgang S. Rupprecht]

Bruno Wolff III <bruno at wolff.to> writes:
> Depending on the file system on the device the following may help you find
> out if any of your bad sectors are in files:
> http://smartmontools.sourceforge.net/badblockhowto.html

I don't trust myself to get all that math right (and guessing about the
underlying remapping).  

What I do is just copy the data to a good disk and then write zeros over
the bad disk.  This will clean up all Current_Pending_Sectors (bad
sectors that haven't been reallocated yet) and turn them into
Reallocated_Sector_Ct sectors.

I'm getting a lot of experience doing this.  For some reason my current
crop of Seagate 7200.11 and 7200.12 are all developing unreadable
sectors.  I guess the Seagate perpendicular recording disks weren't
quite ready for prime time.  Almost -- but not quite.

The fastest way I found to zero the disk is to use the security erase
feature.  A disk that takes 4 hours to be zeroed with dd can be zeroed
in 2 hours with the built-in security erase.  It took me a while to
figure out how to get the security erase hooks to do anything but give
me the "IO ERROR" errno.  This seems to be the simplest way to get an
erase to take place.  (Suggestions and simplifications welcome!)

    disk=/dev/sdb
    pass=funkystuff

    hdparm --user-master u --security-set-pass $pass $disk
    hdparm --user-master u --security-erase    $pass $disk
    hdparm --user-master u --security-disable  $pass $disk

-wolfgang
-- 
Wolfgang S. Rupprecht
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