[Durham] SMART errors

[Richard Mortimer]

On 09/11/2014 16:38, Oliver Burnett-Hall wrote:
> On 9 November 2014 16:09:00 GMT+00:00, David Leggett
> <david+lists+durhamlog at asguard.org.uk> wrote:
>> You can pull out all the smart details from a disk by doing 
>> smarctl -a /dev/sd? and you can tun some tests by doing smartctl
>> -t long /dev/sd? or smartctl -t short /dev/sd?
> 
>> The test will run in the background on the disk controller. Once
>> the test is finished you can get the results of the last few
>> tests by doing smartctl -l selftest /dev/sda
> 
> This is where I'm getting confused: I've run those tests but they
> are not reporting any errors.
> 
I think that David answered your real issue of broken disk but to
answer your confusion...

SMART at times isn't that smart! The self-tests only report on errors
found during the self-test and not based on the general health of the
disk at other times!

In particular if the bits of the disks that are involved in the
selftests aren't faulty then it reports all is fine.

If you suspect that there is trouble on the disk look at the -a output
and you will see lots of error counters. If any of those have any
significant number of errors (especially if they are increasing
rapidly) then that indicates problems. But note that some level of
errors are to be expected due to cosmic rays, read/write alignment or
whatever the magic disk fairy decided to do.

An example from a good disk (6 years and going strong - touch wood).
The only real significant error reported there is Hardware_ECC_Recovered.

Note that you will get different attributes reported for different
models/manufacturers and the values might mean different things too.
So there is a level of 2nd guessing involved in interpreting SMART data.


SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE
UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   100   100   051    Pre-fail
Always       -       0
  3 Spin_Up_Time            0x0007   076   076   011    Pre-fail
Always       -       8150
  4 Start_Stop_Count        0x0032   100   100   000    Old_age
Always       -       143
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail
Always       -       0
  7 Seek_Error_Rate         0x000f   100   100   051    Pre-fail
Always       -       0
  8 Seek_Time_Performance   0x0025   100   100   015    Pre-fail
Offline      -       9721
  9 Power_On_Hours          0x0032   090   090   000    Old_age
Always       -       52675
 10 Spin_Retry_Count        0x0033   100   100   051    Pre-fail
Always       -       0
 11 Calibration_Retry_Count 0x0012   100   100   000    Old_age
Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age
Always       -       41
 13 Read_Soft_Error_Rate    0x000e   100   100   000    Old_age
Always       -       0
183 Runtime_Bad_Block       0x0032   100   100   000    Old_age
Always       -       0
184 End-to-End_Error        0x0033   100   100   000    Pre-fail
Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age
Always       -       1
188 Command_Timeout         0x0032   100   100   000    Old_age
Always       -       0
190 Airflow_Temperature_Cel 0x0022   065   051   000    Old_age
Always       -       35 (Min/Max 27/44)
194 Temperature_Celsius     0x0022   063   049   000    Old_age
Always       -       37 (Min/Max 27/46)
195 Hardware_ECC_Recovered  0x001a   100   100   000    Old_age
Always       -       131947060
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age
Always       -       0
197 Current_Pending_Sector  0x0012   100   100   000    Old_age
Always       -       0
198 Offline_Uncorrectable   0x0030   100   100   000    Old_age
Offline      -       0
199 UDMA_CRC_Error_Count    0x003e   100   100   000    Old_age
Always       -       8
200 Multi_Zone_Error_Rate   0x000a   100   100   000    Old_age
Always       -       0
201 Soft_Read_Error_Rate    0x000a   100   100   000    Old_age
Always       -       0