Well, even single sector less would be a problem, no?
So if we look at current docs for Rev.C the drive should have 23,437,770,752 sectors which the “bad” drive has. https://www.seagate.com/content/dam/seagate/migrated-assets/www-content/product-content/enterprise-hdd-fam/enterprise-capacity-3-5-v7/_shared/docs/100816426c.pdf
I sadly cant find docs for previous revisions so I cant be sure if the number of Guaranteed sectors changed. But it seems quite important change for mere revision.
And for WD drives I cant even find this info… Thats quite bad if person needs to be sure about the number of sectors.
What might be more insidious, though harder to prove unless you crowd source it, is that the “guaranteed sectors” might be the same across the line, yet some revisions or models might have more than what is guaranteed.
In the case of the OP, you can see that all the models are exactly the same, yet only the newer ones have slightly smaller capacities (by about 1.2 GB).
This might mean that the original purchased drives could have “guaranteed” the same amount of sectors, but went over this by a slight margin.
I thought about that too. That “guaranteed sectors” basically means “minimum sectors”.
But I checked my 14TB Seagate and it has the exact number of sectors it should have according to guaranteed sectors in docs.
So I think guaranteed sectors most likely means “exact number of sectors”. Because otherwise I think they would add some reserve it it would be exact.
More people can check their drives and report if the number of sectors is the same as guaranteed sectors in docs.
If it is like you say and HDDs differ in number of sectors (while guaranteed sectors stay the same) its a ticking timebomb for ZFS.
Even changing number of guaranteed sectors per revision is very bad.
1 Like
Looks like even Unraid users are being bit by Seagate’s shenanigans.
You’ll notice he has three 12-TB Seagate drives of the same model as the OP: ST12000NM0127
One of the drive’s total capacity (in bytes):
12001339219968
The other two drives’ total capacity (in bytes):
12000138625024
You’ll notice those two numbers are the same discrepancies that the OP is dealing with.
The user on the Unraid forum incorrectly referred to them as “Western Digitals”, when in fact those model numbers are Seagate.
