CurrentPendingSector

[Robert Nichols]

On 01/28/2015 03:14 PM, Kevin Cummings wrote:
> On 01/28/2015 04:06 PM, Patrick Dupre wrote:
>> Hello,
>>
>> I get:
>> Device: /dev/sdc [SAT], 1 Currently unreadable (pending) sectors
>>
>> How can I manage this issue?
>
> Buy a new disk drive?  Seriously, pending sectors are disk write errors
> and the disk has run out of "extra" blocks to write/re-map them to.  The
> error occurs later when you later attempt to read from them.  It is a
> sign that the disk is is on its way out.

Quote from the FAQ at http://www.smartmontools.org/wiki/FAQ :

   "Normally when an uncorrectable sector is found, the disk puts this
   onto a 'pending sector list' to indicate that it should be replaced
   with a spare good sector. However this replacement won't take place
   until either the disk can read the data on the bad sector, or is
   instructed to write new data to that bad sector."

Pay attention to the "However ...".  First, if you can, look at the
overall health of the drive by running "smartctl -A /dev/sdc".
Attributes 5 (Reallocated_Sector_Ct) and 197 (Current_Pending_Sector)
are of interest.  If the RAW_VALUE numbers for either of those is not
small, it's time to replace the drive.

If those numbers _are_ small, the Bad Block HOWTO at
http://smartmontools.sourceforge.net/badblockhowto.html has instructions
for locating and fixing sectors that are pending reallocation.  If there
are more than a handful of pending sectors, you probably won't want to
go through that fairly tedious procedure for each one.  In that case you
can back up all the data that is recoverable and simply overwrite the
whole drive with zeros to get all those sectors reallocated.

If you continue to get new pending sectors or if the number of
reallocated sectors continues to increase, then the drive should be
replaced. SMART won't declare the drive as failing or near failing until
it _has_used up nearly all its spare sectors, and by then it is long
past the time it should have been replaced.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.