SSD Cache, strange attributes for a not very old drive

[rorton]

I put in a Crucial MX500 as an SSD for Cache. Previous versions of UnRaid didn't have the database updated to show the complete attributes for the device, now I'm on 6.6.1, i can see them all, and was concerned about the SSD Lifetime:

 

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  1 Raw_Read_Error_Rate     POSR-K   100   100   000    -    0
  5 Reallocate_NAND_Blk_Cnt -O--CK   100   100   010    -    0
  9 Power_On_Hours          -O--CK   100   100   000    -    1978
 12 Power_Cycle_Count       -O--CK   100   100   000    -    7
171 Program_Fail_Count      -O--CK   100   100   000    -    0
172 Erase_Fail_Count        -O--CK   100   100   000    -    0
173 Ave_Block-Erase_Count   -O--CK   085   085   000    -    233
174 Unexpect_Power_Loss_Ct  -O--CK   100   100   000    -    3
180 Unused_Reserve_NAND_Blk PO--CK   000   000   000    -    26
183 SATA_Interfac_Downshift -O--CK   100   100   000    -    0
184 Error_Correction_Count  -O--CK   100   100   000    -    0
187 Reported_Uncorrect      -O--CK   100   100   000    -    0
194 Temperature_Celsius     -O---K   072   055   000    -    28 (Min/Max 0/45)
196 Reallocated_Event_Count -O--CK   100   100   000    -    0
197 Current_Pending_Sector  -O--CK   100   100   000    -    0
198 Offline_Uncorrectable   ----CK   100   100   000    -    0
199 UDMA_CRC_Error_Count    -O--CK   100   100   000    -    0
202 Percent_Lifetime_Remain ----CK   085   085   001    -    15
206 Write_Error_Rate        -OSR--   100   100   000    -    0
210 Success_RAIN_Recov_Cnt  -O--CK   100   100   000    -    0
246 Total_Host_Sector_Write -O--CK   100   100   000    -    18932877712
247 Host_Program_Page_Count -O--CK   100   100   000    -    559673637
248 FTL_Program_Page_Count  -O--CK   100   100   000    -    763628335
                            ||||||_ K auto-keep
                            |||||__ C event count
                            ||||___ R error rate
                            |||____ S speed/performance
                            ||_____ O updated online
                            |______ P prefailure warning

If you have a look at 202 - Percent_Lifetime_Remain, the value is 15 - so is that telling me that my SSD, that was new 2 months ago, only has 15% of its lifetime left!!?

Edited October 7, 2018 by rorton

[JonathanM]

Wild guess here, but since the value is 085 and thresh is 001, I'd be more inclined to interpret it as 85% remaining, with a countdown to threshold of 001. Manufacturers sometimes do weird internal things with raw values, but the value, worst, and thresh columns are supposedly their presentation data that you are supposed to base decisions on.

 

Each manufacturer treats this stuff slightly differently, so it's tough to get a universal view.

[rorton]

Thanks that sounds more feasible, but still seems like a Fast reduction in its life span, 15% used in 2 months, it’s not going to last 2 years at this rate