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-   -   Interpreting SMART Data on Corsair SSDs (https://forum.corsair.com/forums/showthread.php?t=89316)

Yellowbeard 09-02-2010 02:44 AM

Interpreting SMART Data on Corsair SSDs
 
3 Attachment(s)
In the last few weeks, I have spent quite a bit of time looking at the SMART data from a variety of Corsair SSDs. This thread is here to address the specific things I have observed about a few popular SMART reporting utilities, the SMART attributes and data, and the Corsair Force series SSDs.

I discovered some very interesting things about SMART monitoring and reporting. SMART as defined by the ATA standard is standardized. However, the structures or methods used by device manufacturers to report SMART attributes and status are not. Although there are some common standards observed across device manufacturers, there are many that are unique to each.

This problem is exacerbated by the fact that many SMART values have what is known as a raw value which is wholly determined by the device manufacturer. This raw value may or may not correctly correspond to a physical unit or normalized value, numbered 1-253. A great example of this is the recent issue of some SMART monitoring utilities reporting SSD temperatures of 156c or more! :flamethro

Additionally, there are a set of SMART attributes that only apply to SSDs. And, even within these SSD specific attributes, there are variations of the terminology used for these attributes. Finally, to completely complicate things, not all SSD controllers report the same SMART attributes.

Many SMART tools were originally only designed to monitor HDDs. Some current tools are adaptations of older SMART utilities that have been modified or updated to include SSD attributes. Unfortunately, due to the variations of SMART attribute reporting across the many different SSD controllers, it is almost impossible to find a tool that is accurate across all brands of controllers AND that also correctly deals with all the SSD specific SMART attributes.

We are working dilligently with SandForce and with the developers of some of the more popular SMART monitoring utilities to improve the accuracy when using these utilities with Corsair SandForce based SSDs. In the mean time, here are some screenshots of some of these issues that you may want to be aware of. In short, if your drive is performing within specification, then you should be skeptical of any SMART utility that is indicating issues.

Keep in mind that this is not a condemnation of each respective software developer or criticism of their efforts. However, we feel it is important to show our customers some examples of what is going on as we work our way through this situation.

An important item of note is the method of determining Health Status or SSD Life Left. Some SSD controllers report an attribute not seen on SandForce attributes, 205 (hex-D0). This attribute is the MAX Program/Erase cycles for the SSD. This attribute is used on some controllers combined with atttribute 5 (Reallocated Sector Count aka Retired Block Count) to determine SSD Life Left. Since this attribute is not reported by the SandForce controller, it is impossible to determine how the monitoring utilities are determining SSD Life Left or Health Status reports.


Crystaldisk 3.7.0

In this example, we can see 2 different temperature attributes reported. Obviously a working drive is not at 0C and there is no raw or normalized value given.

This report is also problematic as the second attribute, E7 (aka 231) is still reported by some tools as a drive temperature. Here it is showing SSD Life Left which is an SSD attribute. However, we have also verified that the SandForce controllers are not currently reporting the E7 attribute correctly. So, we believe that it is not a reliable reporting of SSD Life Left.

As you can see, this drive is new having been cycled only 12 times and been powered on for 3 total hours. I took it out of the box, installed Windows 7, and took these screenshots. It has never been benchmarked. With so little usage, and these reporting anomolies, we don't believe that 96% is an accurate estimate of Health Status for this drive.

http://forum.corsair.com/forums/atta...1&d=1283407396



DiskCheckup

This utility, with a release date of August 19, 2010, shows several Unknown Attributes, some of which are circled in red. These attributes are reported by other tools including CrystalDisk. Therefore, it is unclear why this tool would not show known SMART attributes shown by other utilities.

We again see the E7/231 attribute reported incorrectly as a Temperature.

http://forum.corsair.com/forums/atta...1&d=1283407632



HD Tune

The Health Warning indication for attribute 05 is an erroneous reading. We are looking into this and have not as of yet determined why this occurs. This same drive checked with the SandForce utility does not show any status indicating an issue.

Again, we also see the SSD Life Left attribute E7/231 reported as a temperature. As previously stated, this attribute has been determined to not be reported correctly by the SandForce controller.


http://forum.corsair.com/forums/atta...1&d=1283408447

So what does all of this mean to end users? As stated above, we don't believe that the current SMART tools are completely accurate in their reporting. Our suggestion is to use performance as read by ATTO as a tool to determine if your drive is functioning properly. Remember, no SSD is going to report 100% life left, even fresh out of the box.

Yellowbeard 09-02-2010 02:46 AM

According to our Engineering people, the F40 and F80 drives do not have temperature sensors. So, any temp readings using those drives should be ignored. Also, readings on the other Force drives may still be incorrect with some utilities even after the 2.0 firmware update.

Wired 09-02-2010 08:54 AM

Reserved for future use.

Wired 09-02-2010 08:55 AM

Good article Yellowbeard!

Mummy 09-04-2010 01:11 PM

Hi,
I just "Secure eraser" my F60's with "Parted Magic" thats mostly recommended in here. Do ing it, i find that there is "Smart tool" too.
To my surprise i find that my mb's SMART was "Enabled" ( I was under, understanding that one of my options, make it disable, but no).
Ok, i didnt expect it, but it didnt muther because, it all so sayd "Self test, Passed", for all my SSD's.

Reason why i mention this is, that i dont think those records are correct in it and maybe you Yellowbeard, would like to look in it, too...

Sorry my bad english.
Cheers, Mummy

Toughbook 09-08-2010 07:34 AM

To go along with what YellowBeard has stated. I have a F-120 that is roughly into 3 weeks of use. I have HDTune Pro 4.6 on my system. I am showing the 05 as being a warning as well. What is wierd I find is that the E7 shows a temp of 86, but the temp reading at the top and what shows in my Taskbar is 98 and it does move around a bit. I do feel this reading is correct. Why it would show one temp in the SMART window and then show a different temp elsewere is a great example of what you are describing. I am very glad to read this as I was thinking that maybe my drive is defective.

YB, you stated that your Corsair Utility showed a different reading, what Utility does Corsair use?

Thanks for the info!

fadsarmy 09-24-2010 01:14 PM

How come there is no Corsair Utility to monitor these drives?

gunrunnerjohn 09-24-2010 01:41 PM

1 Attachment(s)
Quote:

Originally Posted by fadsarmy (Post 468090)
How come there is no Corsair Utility to monitor these drives?

I asked that in another thread. ;):

Would this status be accurate? I've only had this drive for a few months, I got it late in April and installed then as well. I loaded Windows 7 on it and have been using it ever since.

Yellowbeard 09-24-2010 02:23 PM

Quote:

Originally Posted by gunrunnerjohn (Post 468097)
Would this status be accurate? I've only had this drive for a few months, I got it late in April and installed then as well. I loaded Windows 7 on it and have been using it ever since.

No, it is in no way reliable.

gunrunnerjohn 09-24-2010 04:44 PM

I hate to think of using it up that fast. :D:

I confess, it would be good to have some indication of the health of the drive.

DimSumGuy83 09-28-2010 06:08 PM

I've decided to get rid of crystaldisk since it doesn't give hardcore, actual facts about SSDs. Now I just rely on ATTO to give me facts about my Nova (probably will start benchmarking once a week or twice a month or something like that.) I also tried using Everest and to my surprise, Everest doesn't even detect my SSD (BIOS and Windows detects it though.) So, it seems like the current S.M.A.R.T technology is complete rubbish when it comes to SSDs.

Yellowbeard 09-28-2010 07:39 PM

Quote:

Originally Posted by DimSumGuy83 (Post 468657)
I've decided to get rid of crystaldisk since it doesn't give hardcore, actual facts about SSDs. Now I just rely on ATTO to give me facts about my Nova (probably will start benchmarking once a week or twice a month or something like that.) I also tried using Everest and to my surprise, Everest doesn't even detect my SSD (BIOS and Windows detects it though.) So, it seems like the current S.M.A.R.T technology is complete rubbish when it comes to SSDs.

It's not the SMART technology itself. It's the lack of standardization in how it's reported combined with the utilities that are inaccurate. It's sort a chicken vs egg argument.

DimSumGuy83 09-28-2010 08:21 PM

But all in all, S.M.A.R.T currently is misleading correct?

Yellowbeard 09-28-2010 08:37 PM

Quote:

Originally Posted by DimSumGuy83 (Post 468689)
But all in all, S.M.A.R.T currently is misleading correct?

Did you actually read the first post? :confused:

DimSumGuy83 09-28-2010 08:51 PM

Whoops, I actually kinda blazed through it and didn't pay too much attention to it (I think I may have A.D.D) :D: Anyways, I'm hoping that someone out there will get the S.M.A.R.T tech down to a tee since benchmarking with ATTO does require you to write to your SSD.


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