Harddisk Paramaters

lord loh. · 09-16-2007, 09:42 AM

I tried to fiddle around with some HardDisk Drive utilities and got the following output from

Code:

smartctl -A /dev/sda1

Code:

=== START OF READ SMART DATA SECTION ===
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   114   085   006    Pre-fail  Always       -       83258829
  3 Spin_Up_Time            0x0003   096   095   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age   Always       -       82
  5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   066   060   030    Pre-fail  Always       -       4275747
  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       280
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age   Always       -       86
187 Unknown_Attribute       0x0032   100   100   000    Old_age   Always       -       0
189 Unknown_Attribute       0x003a   100   100   000    Old_age   Always       -       0
190 Temperature_Celsius     0x0022   053   048   045    Old_age   Always       -       791216175
194 Temperature_Celsius     0x0022   047   052   000    Old_age   Always       -       47 (Lifetime Min/Max 0/28)
195 Hardware_ECC_Recovered  0x001a   062   048   000    Old_age   Always       -       57421795
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

Here is my Hard Disk Specifications.

My concern is the row that states Raw_Read_Error_Rate this figure seems too high... What exactly is it?

If I see the ECC recovery, The number of unrecovered errors is 25837034... Is there something wrong?

bigrigdriver · 09-17-2007, 06:38 AM

The RAW_VALUE numbers have little to do with actual errors that have occured. It is a six-bit number (with more info) that the VALUE (normalized number). The numbers to worry about are VALUE and THRESH. When VALUE gets close to THRESH, the drive is about to fail. I found this, which might ease your mind:

Quote:

Each Attribute has a six-byte raw value (RAW_VALUE) and a one-byte normalized value (VALUE). In this case, the raw value stores three temperatures: the disk's temperature in Celsius (29), plus its lifetime minimum (23) and maximum (33) values. The format of the raw data is vendor-specific and not specified by any standard. To track disk reliability, the disk's firmware converts the raw value to a normalized value ranging from 1 to 253. If this normalized value is less than or equal to the threshold (THRESH), the Attribute is said to have failed, as indicated in the WHEN_FAILED column. The column is empty because none of these Attributes has failed. The lowest (WORST) normalized value also is shown; it is the smallest value attained since SMART was enabled on the disk. The TYPE of the Attribute indicates if Attribute failure means the device has reached the end of its design life (Old_age) or it's an impending disk failure (Pre-fail). For example, disk spin-up time (ID #3) is a prefailure Attribute. If this (or any other prefail Attribute) fails, disk failure is predicted in less than 24 hours.

The names/meanings of Attributes and the interpretation of their raw values is not specified by any standard. Different manufacturers sometimes use the same Attribute ID for different purposes. For this reason, the interpretation of specific Attributes can be modified using the -v option to smartctl; please see the man page for details. For example, some disks use Attribute 9 to store the power-on time of the disk in minutes; the -v 9,minutes option to smartctl correctly modifies the Attribute's interpretation. If your disk model is in the smartmontools database, these -v options are set automatically.

Ignore the part about temperatures. The author was using cpu temp as an example of what smartctrl was reporting. You can see from this that the raw value is not reporting actual number of errors.

lord loh. · 09-29-2007, 12:46 PM

Thank you for the excellent explanation. I was wondering about the column

Code:

  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       280

I assume that the normalized value has reached 100 in 280 hours. So a brand new harddisk should have a value of 253. At this rate, in about 465 hours of operation, my hard disk should reach the end of life cycle... Just 19 days of 24x7 operation... Looks impractical... Where have I gone wrong? Can I predict the failure or the life of a hard disk?

GrapefruiTgirl · 09-29-2007, 01:10 PM

It's more likely that it 'started out as 100' which is normal, rather than 'reached 100 in 280 hours'.
If you check regularly, you will see also that the 'Hours of Operation' value wraps around too, so is not a practical indicator of the age of the drive, nor useful in trying to calculate its life expectancy.

cam34 · 04-07-2008, 10:32 PM

Thanks for this post - I was worried about this line

Code:

1 Raw_Read_Error_Rate     0x000f   068   056   006    Pre-fail  Always       -       105797684

But supposedly Im ok

Thanks - I Hope