SSD DC S3700 Wearout Measuring

[rmare2]

For our product, we are developing with DC S3700 series "INTEL SSDSC2BA400G3" SSDs and we are trying to understand the life span. From the SMART data we get conflicting numbers from the "Total LBAs Written (0xf1)" and "Media Wear out Indicator (0xE9)."

Could you help us understand how to determine SSD Life? And why the two SMART parameters tell a different story?

Intel Spec:

400 GB SSDs should have a life of 7.30 PBW

SMART Data:

"Total LBAs Written": 0xf1 : 100: 100: RAW: 0x00000cc41bab

This translates to 7.18 PB written = (214178731 count)*(65536 sectors/count)*(512 bytes/sector)/(1000^5).

Though, the media wear smart parameter shows 55

"Media Wearout Indicator": 0xe9 : 55: 55: RAW: 0x000000000000

So, why do the "Media Wearout Indicator" and the "Total LBAs Written" when using the drive specification limit differ so greatly?

[Jose_H_Intel1]

These SMART Attributes are different from each other. Here you can read the information:

Total LBAs Written (F1h)

Raw value: reports the total number of sectors written by the host system. The raw value is increased by 1 for every 65,536 sectors (32MB) written by the host.

Normalized value: always 100.

Media Wearout Indicator (E9h)

Raw value: always 0.

Normalized value: reports the number of cycles the NAND media has undergone. Declines linearly from 100 to 1 as the average erase cycle count increases from 0 to the maximum rated cycles.

Once the normalized value reaches 1, the number will not decrease, although it is likely that significant additional wear can be put on the device.

http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ssd-dc-s3700-spec... http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ssd-dc-s3700-spec... (page 23)

[rmare2]

Thank you for your reply, but the information provided does not help me understand why the drive is reporting conflicting numbers for the SMART IDs for "Total LBAs Written (0xf1)" and "Media Wear out Indicator (0xE9)."

The "Total LBAs Written" parameter with reference to the Intel Specification leads one to believe that the drive should be 98% worn out. So how can the MWI be reporting only 55% worn?

My Calculations from the smart data:

From the Drive:

• Media Wear out Indicator: 0xe9 : 55: 55: RAW: 0x000000000000
• Total LBAs Written: 0xf1 : 100: 100: RAW: 0x00000cc41bab

Calculations for total Writes:

0x00000cc41bab => 214178731 count

(214178731 count)*(65536 sectors/count)*(512 bytes/sector)/(1000^5) = 7.18 PB written

In the Intel® SSD DC S3700 Series specification the 400 GB drive is rated for a life span of 7.30 PBW.

Thus, the drive should be about

98% used up: 100*(7.3-7.18)/7.3 = 98%

How then is the Media Wear out indicator 55?

[Jose_H_Intel1]

Please allow us more time to investigate.

[rmare2]

joe_intel,

Thank you for looking into this.

Do you have an update?

Thanks