[kwlug-disc] Media errors on a USB disk

Khalid Baheyeldin kb at 2bits.com
Wed Oct 20 14:37:19 EDT 2010


And here is the interesting part:

e2fsck runs another program. Guess who it is? Top shows this:

badblocks -b 4096 -X -s /dev/sdb1 244190007

So, it is all retro, just under the hood.

On Wed, Oct 20, 2010 at 2:30 PM, Khalid Baheyeldin <kb at 2bits.com> wrote:

> Aha! I knew there has to be something.
>
> I am trying it now. It is very slow on a 1TB drive and USB.
>
> Will report back what it did.
>
> On Wed, Oct 20, 2010 at 1:12 PM, Andrew Sullivan Cant <
> acant at alumni.uwaterloo.ca> wrote:
>
>> As a FLOSS alternative and if you are using ext2/ext3/ext4 then e2fsck
>> will also check for bad blocks and do corrections.
>>
>> e2fsck -c -y /dev/sdb
>> -c will try to detect and fix bad block by adding then to the bad block
>> inode
>> and -y will answer yes to doing all of the corrections. Which is probably
>> what you want most of the time.
>>
>>
>> I have not tried SpinRite so I don't know what additional magic it might
>> do.
>>
>>
>> Andrew
>>
>>
>> On 20/10/10 10:33 AM, Eric Gerlach wrote:
>>
>>> On Wed, Oct 20, 2010 at 10:08 AM, Khalid Baheyeldin<kb at 2bits.com>
>>>  wrote:
>>>
>>>> For the weekly backup, I am now getting this error:
>>>>
>>>> [2388063.441067] sd 13:0:0:0: [sdb] Result: hostbyte=DID_OK
>>>> driverbyte=DRIVER_SENSE,SUGGEST_OK
>>>> [2388063.441073] sd 13:0:0:0: [sdb] Sense Key : Medium Error [current]
>>>> [2388063.441077] sd 13:0:0:0: [sdb] Add. Sense: Unrecovered read error
>>>> [2388063.441080] end_request: I/O error, dev sdb, sector 177045897
>>>> [2388064.495756] sd 13:0:0:0: [sdb] Result: hostbyte=DID_OK
>>>> driverbyte=DRIVER_SENSE,SUGGEST_OK
>>>> [2388064.495762] sd 13:0:0:0: [sdb] Sense Key : Medium Error [current]
>>>> [2388064.495765] sd 13:0:0:0: [sdb] Add. Sense: Unrecovered read error
>>>> [2388064.495768] end_request: I/O error, dev sdb, sector 177045897
>>>>
>>>> If I replace the disk with an identical brand (but has a different make
>>>> of disk inside), I get other errors.
>>>>
>>>> These two disks have been stable and trouble free for about 2 years,
>>>> with no issues.
>>>>
>>>> My questions are:
>>>>
>>>> 1. Short of dd if=/dev/sdb, is there a way to detect blocks?
>>>>
>>>
>>> SpinRite.  Proprietary, but the best I know of.
>>>
>>>  2. Do we have a way to add the bad blocks to a list that the operating
>>>> system
>>>> should ignore, like we had in the old days?
>>>>
>>>
>>> No, now drives do this internally.  Drives keep a percentage of their
>>> sectors as spares, and swap them in when needed.  SpinRite helps the
>>> drive find those bad blocks, recover the data, and then relocate the
>>> blocks.
>>>
>>>  3. Could this be a quirk of some sort? How do I know for sure if it is
>>>> really a media problem or some bug/quirk?
>>>>
>>>
>>> No idea.  I don't even know what those errors mean, so I can't even
>>> confirm for sure that it's bad blocks.
>>>
>>> Cheers,
>>>
>>> Eric
>>>
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>>>
>>
>>
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>>
>
>
>
> --
> Khalid M. Baheyeldin
> 2bits.com, Inc.
> http://2bits.com
> Drupal optimization, development, customization and consulting.
> Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
> Simplicity is the ultimate sophistication. --   Leonardo da Vinci
>



-- 
Khalid M. Baheyeldin
2bits.com, Inc.
http://2bits.com
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
Simplicity is the ultimate sophistication. --   Leonardo da Vinci
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