[plug] Failing disk drive

Adam Davin byteme-its at westnet.com.au
Tue Apr 15 10:39:31 WST 2008


Hi Richard, 

On Tue, 15 Apr 2008 10:11:08 +0800
Richard Meyer <meyerri at westnet.com.au> wrote:

> 
> OK, so if it says it's allocated all the alternate
> blocks/tracks/whatever, they're still gone afterwards, and cannot be
> reclaimed (except by manufacturer's tools)?
> 
> On Mon, 2008-04-14 at 19:05 -0700, Fred Janon wrote:
> > Nope, the stats are stored in the drive by the drive firmware. Some
> > are resettable by commands and some aren't if I remember correctly.
> > The issue is that there is no real 100% standard for SMART and you
> > need the manufacturer tools for the specific drives most likely.
> > 
<snip> 

I get the following messages in my syslog from the smartd monitor:

Apr  9 20:33:27 owl smartd[23109]: Device: /dev/hda, SMART Prefailure
Attribute: 1 Raw_Read_Error_Rate changed from 58 to 59 
Apr  9 20:33:27 owl smartd[23109]: Device: /dev/hda, SMART Prefailure
Attribute: 1 Raw_Read_Error_Rate changed from 58 to 59 

Apr 10 06:33:27 owl smartd[23109]: Device: /dev/hda, SMART Prefailure
Attribute: 1 Raw_Read_Error_Rate changed from 59 to 58 
Apr 10 06:33:27 owl smartd[23109]: Device: /dev/hda, SMART Usage
Attribute: 195 Hardware_ECC_Recovered changed from 59 to 58 

Apr 11 02:33:27 owl smartd[23109]: Device: /dev/hda, SMART Prefailure
Attribute: 1 Raw_Read_Error_Rate changed from 58 to 57 
Apr 11 02:33:27 owl smartd[23109]: Device: /dev/hda, SMART Usage
Attribute: 195 Hardware_ECC_Recovered changed from 58 to 57 

Apr 12 21:33:27 owl smartd[23109]: Device: /dev/hda, SMART Prefailure
Attribute: 1 Raw_Read_Error_Rate changed from 57 to 58 
Apr 12 21:33:27 owl smartd[23109]: Device: /dev/hda, SMART Usage
Attribute: 195 Hardware_ECC_Recovered changed from 57 to 58 

Which suggests that the drive may re-test bad errors and reallocate
these if it finds them still "ok". Though I could be well wrong in
these assumptions... 

It looks to me like the drive is pre-empting an error and "replacing"
the sector just in case (tm) then rechecking the sector more
thoroughly later on to then allow them back into service if they pass.. 

Regards, 

-- 

Adam Davin
Byteme IT Services
Mob: 0422 893 898
Fax: 08 9493 4462
Email: byteme-its at westnet.com.au



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