# Deciphering SMART disk diagnostics



## PhilG (Jan 15, 2002)

My Tivo has started doing "odd" things and I am wondering if the disk is on the way out (I'm getting random reboots, garbled recordings, recordings with no sound, intermittend pixellation etc)

Luckily I have a modified dailymail that ALWAYS outputs the results of the SMART diagnostic and I have some outout from 3 years ago

Then it said



> SMART Attributes Data Structure revision number: 16
> Vendor Specific SMART Attributes with Thresholds:
> ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE WHEN_FAILED RAW_VALUE
> 1 Raw_Read_Error_Rate 0x000f 100 100 051 Old_age - 0
> ...


Whereas todays says



> SMART Attributes Data Structure revision number: 16
> Vendor Specific SMART Attributes with Thresholds:
> ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE WHEN_FAILED RAW_VALUE
> 1 Raw_Read_Error_Rate 0x000f 100 100 051 Old_age - 1
> ...


I'm impressed that the power-on-hours has increased almost exactly as I'd expected (just over 3 years) BUT the "Hardware_ECC_Recovered" (which is where I'd expected to see any evidence of disk, troubles) has gone DOWN from 53,647,912 to 34,052,475 

I'd be happy if disks got BETTER with age, but it's unlikely

I'm just wondering if anyone can shed any light - in the meantime, I'll see what it says tomorrow

Phil G


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## Ian_m (Jan 9, 2001)

You need to get the OEM datasheet (probably on NDA) to understand what "Hardware_ECC_Recovered" means. Generally the higher number SMART parameters are manufacturer specific and are most likely internal diagnostics.

The most important one is "Reallocated_Sector_Ct", anything other than 0 is indication of a failing disk and should be replaced.

We have just has a misbehaving RAID array in a server at work and one of the disks had a "Reallocated_Sector_Ct" of 152 (and failed SMART tests).


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## PhilG (Jan 15, 2002)

Thanks for that - I think I'll sit on this for a while and see what happens....

Just out of interest, that hardware_ecc_recovered value was 37,284,310 this morning - up from 34,052,475 yesterday......

Smart also reports the drive as



> Device Model: SAMSUNG HA250JC
> Serial Number: S094J10A139708


If anyone has intimate knowledge of those

And isn't it interesting that I thought that 250Gb was HUGE when I installed it 3 years ago, and now I'm sitting here thinking "Hmm - Only 250Gb. I thought it was bigger than that" 

I would swap it for something bigger, but Tivo is at the very bottom of an equipment stack and I'm afraid to touch any of it 'cos cables fall out at the slightest provocation and it's all in a cupboard I can't get to the back of


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## iankb (Oct 9, 2000)

PhilG said:


> ... I thought that 250Gb was HUGE when I installed it 3 years ago, and now I'm sitting here thinking "Hmm - Only 250Gb. I thought it was bigger than that"


Think yourself lucky that you're only recording SD. Until BBC changed their algorithms a few months ago, some of my BBC HD recordings were up to 25GB in size. Now they're only half of that. 

I currently have over 2TB storage on my Media Center, and that only has one part-time HD channel at the moment.

It will be interesting as to how expandable the new Virgin hardware will be, given the ability to record HD. Either they will need to allow external expansion, or most people will have to rely on VOD. Although I suppose Sky HD users are already living with that problem.

_- I assume that you meant 250GB (gigabyte), and not 250Gb (gigabit)._


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