Author: James Courtier-Dutton Date: To: Hampshire LUG Discussion List Subject: Re: [Hampshire] [OT] MTBF
2009/7/20 Stephen Rowles <stephen@???>: > James Courtier-Dutton wrote:
>> I think people don't seem to realize that HDs have very low resistance
>> to shock while switched on, and this is the main cause of HD failures.
>> Most (all?) modern HDDs have a whole raft of sensors and store life time
>> information about read errors, temperature range etc. etc. this is SMART
>> (you might see on the bios screen). In Linux you can query this using
>> smartctl:
>
> ~]# smartctl --all /dev/sda
>
> For example the stats from my current drive here at work:
>
> SMART Attributes Data Structure revision number: 10
> 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 108 093 006 Pre-fail
> Always - 16203744
> 3 Spin_Up_Time 0x0003 098 095 070 Pre-fail
> Always - 0
> 4 Start_Stop_Count 0x0032 100 100 020 Old_age
> Always - 69
> 5 Reallocated_Sector_Ct 0x0033 100 100 036 Pre-fail
> Always - 0
> 7 Seek_Error_Rate 0x000f 081 060 030 Pre-fail
> Always - 139114079
> 9 Power_On_Hours 0x0032 088 088 000 Old_age
> Always - 11202
> 10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail
> Always - 0
> 12 Power_Cycle_Count 0x0032 100 100 020 Old_age
> Always - 99
> 187 Reported_Uncorrect 0x0032 100 100 000 Old_age
> Always - 0
> 189 High_Fly_Writes 0x003a 100 100 000 Old_age
> Always - 0
> 190 Airflow_Temperature_Cel 0x0022 061 057 045 Old_age
> Always - 39 (Lifetime Min/Max 21/43)
> 194 Temperature_Celsius 0x0022 039 043 000 Old_age
> Always - 39 (0 19 0 0)
> 195 Hardware_ECC_Recovered 0x001a 064 060 000 Old_age
> Always - 164354431
> 197 Current_Pending_Sector 0x0012 100 100 000 Old_age
> Always - 0
> 198 Offline_Uncorrectable 0x0010 100 100 000 Old_age
> Offline - 0
> 199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age
> Always - 0
> 200 Multi_Zone_Error_Rate 0x0000 100 253 000 Old_age
> Offline - 0
> 202 TA_Increase_Count 0x0032 100 253 000 Old_age
> Always - 0
>
> You can see all sorts of interesting things here which can easily be
> used to warn on pending failure of a drive.
>
> Also most laptop drives now have accelerometers which will detect any
> dangerous shock conditions and park the drive heads to prevent further
> damage to the drive. I cannot find it now but I watched a video on the
None of the above smart parameters give any indication from the accelerometers.
So, one has no way of telling if shock was a contributing factor to
the HD failure.
It would be nice to see smart stats saying, we got this much shock
before we managed to park the heads.
Another thing, for the pre-fail smarts like:
Raw_Read_Error_Rate 16203744
Seek_Error_Rate 139114079
Hardware_ECC_Recovered 164354431
What is an acceptable value and what indicates things starting to go wrong?
My laptop HD has these values at zero!!!
On my desktop, they keep increasing over time. So, what is an
acceptable "rate" ?
