Question Samsung EVO uses Secret Non-Industry Standard for “Wear Leveling Count”.

BretAB

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Mar 14, 2017
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Hi Tom'sHardware,

A little background first: “Wear Leveling Count” is a S.M.A.R.T. attribute of SSDs. It’s Attribute# 177 and, “… indicates the difference (in percent) of the most worn block and the least worn block.” In more practical terms, it’s one of several indicators of how worn out an SSD is. The wear leveling attribute of most manufacturers is stated as a percentage of 100 (with 100 being a new SSD). For example, a 92 would mean it's 8% used/depleted/worn. That said . . .

Periodically I take screen shots of the SMART Attribute data of some of my critical drives. I use the (imho) great open source app GSmartControl to display the attributes. A couple weeks ago, I took a shot of an 860 EVO 250GB (Model MZ-76E250) put in service early in 2018. I saw an odd number “12” in the Wear leveling Count attribute (ie. attribute # 177). Then I compared that screen shot to a couple others I made since 2018. I found that attribute moved from the “0” I noted when it was new in 2018, to the “12” I saw on 11/20/19. It was “0” at first, then went to “2” several months later, then to “10” months later, and the 11/20/19 number “12”. It’s been a couple weeks since 11/20 so I looked today and I see it’s “13”. Here’s a couple pics of the drive specs and attribute data:
Oops, "Insert Image" not working in this forum ("Something went wrong, please try again or contact the administrator"), so here's the link:
https://1drv.ms/u/s!ArzLg8uNtUZ3iDkobDEa65_ybbmq
and
https://1drv.ms/u/s!ArzLg8uNtUZ3iDrbBltbwKpZpBR5?e=59bCLM

The drive is still under warranty so I decide to ask Samsung support about their unusual #177 numbers. Sounds easy enough right? You won’t believe the brick wall that I ran into on this.

On 11/20 I submitted the support case online. Basically it was the “Periodically I take screenshots…” paragraph above. Later that day I received a reply, “Please provide a screenshot or picture of the information you are seeing under your SMART attributes.” I pasted two pics seen above the html email and sent it on its way. The I receive a reply, “We have received your comment. A team member will address your request as soon as possible.” I think that’s great, I should have an answer soon. I note that the embedded pics I sent were not in the reply I just received, so I put the pics in a small pdf and forward that to them also (just in case).

I forget about this support case and 5 days go by with no answer from Samsung. So on 11/26 I forward them their last reply and ask, “I haven’t had a reply on this yet. On 11/20 I sent you the information <pics> you requested. Is there a problem?”

A week goes by without a reply. So on 12/3 I forward the email case to a different Samsung SSD support email address that I’m aware of. I say, “Hi Samsung, I’m not getting any replies on my support inquiry to “support email address1” and that is frustrating. So today I’m trying this to your “support email address2” address, as follows: I haven’t had a reply on this yet. On 11/20 I sent you the information you requested. See “… 2019-11-20 14:13:18 “ and also the link to document1.pdf below. Is there a problem? Please advise . . .” Later that morning I receive their reply, “We have received your comment. A team member will address your request as soon as possible.” Finally I think, this will get answered.

Later that afternoon, I receive their reply, “Your support ticket has been updated. As always, it is our pleasure to assist in any way possible!”. And here’s the real slap in the face: Below that “…pleasure to assist…” line there’s a comment box they filled out, it says, “Dear Customer, We apologize for the inconvenience, we have not yet replied as your request for SMART information has been escalated, Samsung does not typically provide information regarding Samsung internal standards when it comes to drive on board controller information. We have made a request for this information, however due to the holiday delays we have not received an update as of yet, as soon as an update is available we will contact you via this ticket. Your ticket number is xxxxxxxx.”.

Today is 12/5. It’s been two days and it’s become obvious to me Samsung is not going to answer this question. Since Samsung decided to ignore what I consider a legitimate professional request, I’ve made that decision for them and decided to go public with this stonewalling.

It’s my opinion that if the IT community cannot ascertain the health of an SSD using standard industry tools and industry standard attributes, then we shouldn’t buy their products. I’m very concerned that Samsung would choose to shroud the Attribute 177 in some kind of secrecy. It’s like they don’t want us to know the exact health of their storage devices. What are they hiding?

I look forward to your comments, corrections, suggestions and directly related discussions.

Regards,
Bret
 
There is no official standard for SMART attributes. Each vendor is free to use their own format for SMART attributes, and in fact they do. Moreover, the SMART attribute definitions often vary between different models from the same vendor, and even between different firmware for the same model.

So to answer your question, attribute #177 may be a wear levelling count for one SSD, but may mean something completely different for other SSDs.
 

BretAB

Commendable
Mar 14, 2017
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Hi fzabkar,

Thank you for your reply : )

Yes, I agree that manufacturer's frequently use their own yardsticks when displaying their SMART data. Imho that is unfortunate as I and other IT persons feel that standardized values are much better for the hardware involved community. Manufacturers should support the standardization so we can compare apples to apples.

With regard to Samsung and the EVO SSD being discussed, I really don't care if they use icons of penguins to report #177 values. I just want to know what numerical value those penquins represent in terms percent of wear leveling. For example, do 13 penguins mean 13% worn? I don't think this is too much to ask of Samsung. Would you not agree?

Please, other forum members (and even Samsung) feel free to jump in here!

Regards . . .
 
I agree that all vendors should provide detailed specifications for their SMART attributes.

I would also like to see circuit diagrams, technical reference manuals, real diagnostic software, and data recovery software at the firmware level. I had access to this sort of stuff 30 years ago, but nowadays we get little more than marketing pap.
 

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