[smartmontools-support] Inconsistent long test times

[Christian Franke]

Kent Watsen wrote:
>
> Here’s " the "TRIM Command” line from the "--all” output for each device type:
>
>      Seagate Barracuda:	TRIM Command:     Available
>      WD WD20SPZX:	TRIM Command:     Available, deterministic
>      Intel DC 3700 SSD*:	TRIM Command:     Available, deterministic, zeroed

Results from two other SMR disks:
   Seagate ST4000DM004-2CV104: Unavailable
   WDC WD40EZAZ-00SF3B0: Available, deterministic, zeroed


> I’m new to all this, but does “Available" mean that all of these drives do in fact support that which the posters are wishing for?  I assume that “deterministic” refers to DRAT and "deterministic, zeroed” refers to DZAT.

The names introduced in ATA ACS 3:
deterministic:Deterministic Read After Trim (DRAT)
deterministic, zeroed: Read Zeroes After Trim (RZAT)
... which means the same as: Deterministic (read) Zero After Trim (DZAT)


> Given the differences, could it be that, in order for a SMR-based disk to the wiped, it must be "Available, deterministic” (not just “Available”)?

Any "Available" TRIM support should be sufficient. Non-deterministic 
reads after TRIM may be not favorable in certain cases (diagnostics, 
disk image creation, ...)

Regards,
Christian