14 Replies Latest reply on Feb 19, 2015 11:05 AM by jonathan_intel

    SSD DC S3700 Wearout Measuring

    wlrm04

      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?

        • 1. Re: SSD DC S3700 Wearout Measuring
          joe_intel

          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.pdf (page 23)

          • 2. Re: SSD DC S3700 Wearout Measuring
            wlrm04

            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?

            • 3. Re: SSD DC S3700 Wearout Measuring
              joe_intel

              Please allow us more time to investigate.

              • 4. Re: SSD DC S3700 Wearout Measuring
                wlrm04

                joe_intel,

                Thank you for looking into this.

                Do you have an update?

                Thanks

                • 5. Re: SSD DC S3700 Wearout Measuring
                  jonathan_intel

                  Hello wlrm04,

                   

                  We are checking if there has been any progress regarding your inquiry. We will keep you informed as soon as we have an update.

                  • 6. Re: SSD DC S3700 Wearout Measuring
                    jonathan_intel

                    Please let us know the method you are using to get 0xe9 value.

                    - Application name and version. For example: HDParm, SmarmonTools, or other.

                    - Operating System

                     

                    Have you noticed any difference in the values since the original post?

                    • 7. Re: SSD DC S3700 Wearout Measuring
                      wlrm04

                      ----------------------------------------------------------------------------
                      CrystalDiskInfo 5.6.2 (C) 2008-2013 hiyohiyo
                                                      Crystal Dew World : http://crystalmark.info/
                      ----------------------------------------------------------------------------

                          OS : Windows 7 Professional SP1 [6.1 Build 7601] (x64)
                        Date : 2015/01/16 11:40:23

                      ----------------------------------------------------------------------------
                      -- S.M.A.R.T. --------------------------------------------------------------
                      ID Cur Wor Thr RawValues(6) Attribute Name
                      05 100 100 __0 000000000000 Re-Allocated Sector Count
                      09 100 100 __0 000000001FD0 Power-On Hours Count
                      0C 100 100 __0 000000000B75 Power Cycle Count
                      AA 100 100 _10 000000000000 Available Reserved Space
                      AB 100 100 __0 000000000000 Program Fail Count
                      AC 100 100 __0 000000000000 Erase Fail Count
                      AE 100 100 __0 000000000B53 Unexpected Power Loss
                      AF 100 100 _10 001D00000298 Power Loss Protection Failure
                      B7 100 100 __0 000000000291 SATA Downshift Count
                      B8 100 100 _90 000000000000 End to End Error Detection Count
                      BB 100 100 __0 000000000000 Uncorrectable Error Count
                      BE _86 _86 __0 00000E0D000E Temperature
                      C0 100 100 __0 000000000B53 Unsafe Shutdown Count
                      C2 100 100 __0 00000000000E Temperature
                      C5 100 100 __0 000000000000 Pending Sector Count
                      C7 100 100 __0 000000000F9C CRC Error Count
                      E1 100 100 __0 00000CC5236A Host Writes
                      E2 100 100 __0 00000000FFFF Timed Workload Media Wear
                      E3 100 100 __0 0000FFFFFFFF Timed Workload Host Read/Write Ratio
                      E4 100 100 __0 00000000FFFF Timed Workload Timer
                      E8 100 100 _10 000000000000 Available Reserved Space
                      E9 _55 _55 __0 000000000000 Media Wearout Indicator
                      EA 100 100 __0 000000000000 Vendor Specific
                      F1 100 100 __0 00000CC5236A Total LBAs Written
                      F2 100 100 __0 00000016F8E0 Total LBAs Read

                      • 8. Re: SSD DC S3700 Wearout Measuring
                        jonathan_intel

                        Hello wlrm04,

                         

                        We would like to provide the following information about this topic:

                         

                        The Media Wearout Indicator and the Endurance ratings do not have a direct relation. The E9h SMART attribute will not match wear calculation based on the LBA's written.

                         

                        - The reliability values in the product specifications are a minimum expected for Intel® Solid-State Drives.

                        The Endurance rating is calculated using Global standards. It is defined using JESD218 testing method and and JESD219 workloads. However, we expect our drives to exceed those values in almost all cases.

                         

                        - The Media Wearout Indicator is calculated by comparing the actual number of Program/Erase (P/E) cycles experienced by the NAND chips, to the maximum number of P/E cycles that the chips are designed to endure. It does not compare the amount of bytes written to the Endurance values in the Spec sheet.

                        This makes the Media Wearout Indicator a true indicator of the wear of the chips.

                        • 9. Re: SSD DC S3700 Wearout Measuring
                          wlrm04

                          Thank you for your reply on this topic.

                           

                          Do you have a recommendation as to how we can deterministically have our systems warn us based on our write rate when a drive will fail in a month?

                           

                          The "Media Wearout" indicator does not seem to give the user the ability to estimate how much more the user can use the SSD before the indicator is 1. 

                           

                          For our product, we liked the ability to use the written count so that we could have a user deterministic method to say our product with Intel SSDs should be able to last about X amount of time based on current SMART status and our write rate.  Of course, we do not want to replace SSDs that are still good.

                           


                          • 10. Re: SSD DC S3700 Wearout Measuring
                            jonathan_intel

                            We will check with our resources about you inquiry and will let you know once we have more information.

                            • 11. Re: SSD DC S3700 Wearout Measuring
                              jonathan_intel

                              Hello Wlrm04,

                               

                              The monitoring tools provided by Intel for this drive (Intel® Solid-State Drive Data Center Tool and Intel® Solid-State Drive Toolbox) do not include the option to send emails or notifications, they are basic tools designed to manage and monitor the drive upon user request.

                               

                              There are a variety of storage management solutions and system monitoring applications in the market that can monitor S.M.A.R.T. data and send alerts when appropriate. Intel does not recommend one over the other so we advise you to research about the different options available.

                              • 12. Re: SSD DC S3700 Wearout Measuring
                                wlrm04

                                Hello jonathan_intel,

                                 

                                I humbly request that you may have missed answered my question.  My question was related to understanding life left based on SMART values.  I am not asking about system monitoring tools in the market.

                                 

                                Following your recommendation of using the "Media Wearout" indicator, is there a deterministic way to calculate the time to move from 10 to 1 for the "Media Wearout" indicator?

                                • 13. Re: SSD DC S3700 Wearout Measuring
                                  jonathan_intel

                                  Wlrm04, I apologize for the confusion, we were under the impression that you were looking for way to receive a warning if Media Wearout Indicator or other SMART counter was about to reach the advertised threshold or a specific value.

                                   

                                  We appreciate your feedback and will check if there is a way to do the calculation you mentioned. We will get back as soon as we have more information.

                                  • 14. Re: SSD DC S3700 Wearout Measuring
                                    jonathan_intel

                                    Hello Wlrm04,

                                     

                                    We reviewed the details of your request and the Timed Workload Endurance Indicators functionality in our SSD’s may help in this situation. The Timed Workload Endurance attributes are used to measure the amount of media wear that the drive is subjected to during a timed workload.

                                     

                                    If the Intel® SSD DC S3700 has a consistent and typical workload, you can do the test using the Timed Workload Indicators. The results may help you estimate how much time the Media Wearout Indicator might take to decrease to a specific value, for example, from 10 to 1 as you mentioned before.

                                     

                                    Section 5.4.1.1, in pages 24-26, of the Intel® Solid-State Drive DC S3700 Series Product specifications has a good description of how to use the timer and related counters to estimate the endurance impact or your typical workload.