Uncertain about SMART value "Seek_Error_Rate"

[angelus249]

Hi folks,

sorry in advance, but I read so much about that and now I can't tell right from wrong anymore . Some brief advice/opinion would be highly appreciated.

After burning in my new drives, my Seagate 4TB drive (ST4000VN000-2AH166) leaves me uncertain about the Seek_Error_Rate.

Code:

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   082   065   044	Pre-fail  Always	   -	   143023178
  3 Spin_Up_Time			0x0003   098   098   000	Pre-fail  Always	   -	   0
  4 Start_Stop_Count		0x0032   100   100   020	Old_age   Always	   -	   3
  5 Reallocated_Sector_Ct   0x0033   100   100   010	Pre-fail  Always	   -	   0
  7 Seek_Error_Rate		 0x000f   074   060   045	Pre-fail  Always	   -	   24401266
  9 Power_On_Hours		  0x0032   100   100   000	Old_age   Always	   -	   118 (161 91 0)
 10 Spin_Retry_Count		0x0013   100   100   097	Pre-fail  Always	   -	   0
 12 Power_Cycle_Count	   0x0032   100   100   020	Old_age   Always	   -	   3
184 End-to-End_Error		0x0032   100   100   099	Old_age   Always	   -	   0
187 Reported_Uncorrect	  0x0032   100   100   000	Old_age   Always	   -	   0
188 Command_Timeout		 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   071   066   040	Old_age   Always	   -	   29 (Min/Max 27/34)
191 G-Sense_Error_Rate	  0x0032   100   100   000	Old_age   Always	   -	   0
192 Power-Off_Retract_Count 0x0032   100   100   000	Old_age   Always	   -	   1
193 Load_Cycle_Count		0x0032   100   100   000	Old_age   Always	   -	   14
194 Temperature_Celsius	 0x0022   029   040   000	Old_age   Always	   -	   29 (0 18 0 0 0)
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
240 Head_Flying_Hours	   0x0000   100   253   000	Old_age   Offline	  -	   117 (246 206 0)
241 Total_LBAs_Written	  0x0000   100   253   000	Old_age   Offline	  -	   31421501120
242 Total_LBAs_Read		 0x0000   100   253   000	Old_age   Offline	  -	   31256272836

All the other values look good, it's just the normalized value of the Seek_Error_Rate seems already degraded. Currently 74, worst 60, threshold 45. The worst of 60 seems awefully close to 45 considering it's a brand new drive.

I also bought a bunch of WD Red 8TB and they all show a Seek_Error_Rate value of 100, worst also 100, Threashold 67. So no issues here. But it's a different vendor, different size, etc.

Should I RMA the drive before putting it into a live environment? Or can I use it anyway?

Cheers

 

[Ericloewe]

Currently 74, worst 60, threshold 45. The worst of 60 seems awefully close to 45 considering it's a brand new drive.

How would you know? Those values are close to meaningless to anyone except the engineers who designed the thing.

I also bought a bunch of WD Red 8TB and they all show a Seek_Error_Rate value of 100, worst also 100, Threashold 67.

It's really not comparable. Seagate, especially, is known for crazy encodings that might be useful for their engineers to quickly debug stuff without access to lower-level data, but is nearly useless to outsiders.

Should I RMA the drive before putting it into a live environment?

They wouldn't approve it anyway.

 

[angelus249]

Awesome feedback, @Ericloewe
Thanks. Then I can use the drive regardless.

Cheers

 

[Magius]

Just to compound on what Eric said, Seagate is infamous for these proprietary SMART encodings that mean absolutely nothing to us users in raw form. There are some other attributes with similar behavior from other suppliers, but Seagate is by far the most well known for it. In particular, for any attribute with the word "rate" in the name, you should give up on ever understanding what it means. :D

I say this as someone who has held NDAs with several drive manufacturers (never Seagate, unfortunately) so that I could get details on their otherwise proprietary SMART encodings for my work. I also wrote a small SMART utility that FreeNAS 10 uses under the hood to get data from your disk drives. ;)

Believe it or not, I actually used to know the secret to decoding Seagate's raw read error rate (which may or may not have been the same as seek error rate which you asked about) almost a decade ago. It was something along the lines of: take the raw value, '143023178' in your case, and write it out as (32?) bits of binary. Then take the first <some number> of those bits (8?) and convert them back to decimal. This will be a small number, like 1 or 2. Do the same for the remaining bits (24?) to get another (large) decimal number, like a few million. So you now have two numbers, '2' out of 'some million'. That represented the number of raw read errors (2) out of the total number of read operations (some million) that had occurred in the last <measurement period>. And of course that measurement period was a sliding window, so as errors fell out of the window it would change back to '0' of out 'some million', etc. The thing is, with that description you'd think you could leave the disk alone and not read from it for some time, and then get back a '0' raw value (0 errors out of 0 operations) but that wasn't possible, so who knows, maybe even what I thought I knew as the secret was still wrong. :p Either way, the resulting information was still useless (IMHO) for any practical purpose, so I wouldn't worry about it.

As regular users, we all love companies that put every nitnoid detail about their SMART attributes in the data sheets, but there are many out there (I won't name names) who won't even tell you in the data sheet which ID maps to which attribute, never mind how to decode them from raw to anything meaningful. Or one of my "favorites" was Toshiba controllers that hard-coded more than half their raw values to '0' in firmware, so they would never change (this info was provided in the datasheet, so nothing secret, not a bug, just by design). Unfortunately some companies won't even answer a question like "does your drive contain an attribute to indicate life left % or LBAs written" until after signing NDAs... Makes my job a real pain sometimes, but whenever there's an option, I just don't buy their drives if they aren't forthcoming about SMART! :D