It used to be that WD's drives would hit a SMART threshold when the number of reallocated sectors reached 500.

Here is a WD40NDZW that has racked up 50,392 reallocations (= 6299 physical sectors):



The normalised value has dropped from 200 to 182, so this suggests that the drive is spec'ed for 20,000 reallocated physical sectors.

50392 / 8 / (200 - 182) x (200 -140) = 20997
50392 / 8 / (200 - 181) x (200 -140) = 19892

Seagate has been doing this for many years, but I hadn't noticed that WD's drives had also gone down this path.

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A backup a day keeps DR away.

Is that how this works with 4k sectors? I didn't know this.

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Joep - http://www.disktuna.com - video & photo repair & recovery service

I assumed so, but now I see that the pending sector count is 10 which is not a multiple of 8. :-?

The drive in the following thread does seem to fit my assumption, though:

https://forum.hddguru.com/viewtopic.php?f=1&t=41771

This WD40NDZW SMART report suggests that attributes #5 and #196 count logical sectors whereas #197 counts physical sectors:

https://bbs.archlinux.org/viewtopic.php?id=260538

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A backup a day keeps DR away.

I have always wondered about 'event count' too. What does it actually count. Can it do multiple sectors in one 'event' and would it count it as one event? reason I wondered was seeing different numbers for reallocated and reallocation events.

TBH I have never actually seen the format in which sector reallocation are kept. I'm sure you know Frank, can it reallocate a range and then log it as one event?

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Joep - http://www.disktuna.com - video & photo repair & recovery service

I don't know, either.

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A backup a day keeps DR away.