So, another petabyte written and the disk is still working well - no unrecoverable errors so far and no drop in performance. Sector fails are creeping up steadily - just under 800 to date - but so far all these have occurred when the flash was being erased rather than written to. The SSD controller appears to be coping fine, allocating spare sectors from its reserved pool (14% used, 86% remaining):
ID# ATTRIBUTE_NAME VALUE WORST THRESH TYPE RAW_VALUE 5 Reallocated_Sector_Ct 086 086 010 Pre-fail 797 9 Power_On_Hours 099 099 000 Old_age 3034 12 Power_Cycle_Count 099 099 000 Old_age 169 177 Wear_Leveling_Count 053 053 000 Pre-fail 2788 179 Used_Rsvd_Blk_Cnt_Tot 086 086 010 Pre-fail 797 181 Program_Fail_Cnt_Total 100 100 010 Old_age 0 182 Erase_Fail_Count_Total 086 086 010 Old_age 797 183 Runtime_Bad_Block 086 086 010 Pre-fail 797 187 Reported_Uncorrect 100 100 000 Old_age 0 190 Airflow_Temperature_Cel 065 060 000 Old_age 35 195 Hardware_ECC_Recovered 200 200 000 Old_age 0 199 UDMA_CRC_Error_Count 100 100 000 Old_age 0 235 Unknown_Attribute 099 099 000 Old_age 30 241 Total_LBAs_Written 097 097 000 Old_age 5859439678108
The disk that was rated for 150TB of writes has now reached 20 times that and still has life in it. But there will be a cost - it is likely that the data retention period when powered off is much less than the warranted 12 months. When powered on, the controller should periodically check that all cells are readable and swap out any looking a bit dodgy.
As previously, we will now conduct a mini retention test by powering the disk off for a week, and then checking that we can read back the huge file filling it correctly.