Quote Originally Posted by johnw View Post
Yes, I tried and failed, then had a small catastrophe. (snip)

Although the Samsung performed admirably I can’t help think that it should have flagged up a warning (via SMART) once a critical endurance threshold had been reached, which then switched the drive to read only after a warning period. At least it would then have failed gracefully.

According to JEDEC218A “The SSD manufacturer shall establish an endurance rating for an SSD that represents the maximum number of terabytes that may be written by a host to the SSD” It then outlines integrity conditions that the SSD must retain after the maximum amount of data has been written:

1) The SSD maintains its capacity
2) The SSD maintains the required UBER for its application class
3) The SSD meets the required functional failure requirement (FFR) for its application class
4) The SSD retains data with power off for the required time for its application class

The functional failure requirement for retention of data in a powered off condition is specified as 1 year for Client applications and 3 months for Enterprise (subject to temperature boundaries).

I’m really not sure why the MWI appears to be so conservative. Does it really represent a point in time when the endurance threshold to maintain integrity (according to JEDEC specs) has passed? The Samsung wrote over 3 ½ times the data required to expire the MWI. Are you really supposed to throw it away when the MWI expires?

It will be really interesting to see what One_Hertz can uncover on the condition of the NAND.

Anyway I came across an interesting paper from SMART Modular Technologies. This is the second time I’ve seen compressibility referred to as data randomness. Anyone know the issues related to why randomness of data is linked to compressibility?