> It's to the point that if you read an entire disk 4TB you have a 32% chance of one bit being wrong!
If this were the case, forums would be filled to the brim with ZFS users whinging about how they get CKSUM errors practically every time they scrubbed their pools. They do happen, but nothing like that frequently.
> That means hard disks can no longer be considered reliable devices that return the data written to them
They were never such devices in the first place if you ever valued your data enough to care. Even if your disks are perfect, your cabling, backplanes, IO controllers, drivers or memory probably aren't.
> If this were the case, forums would be filled to the brim with ZFS users whinging about how they get CKSUM errors practically every time they scrubbed their pools. They do happen, but nothing like that frequently.
I'm going by what the manufacturers say - are you saying they are overestimating the error rate? Why would they do that?
> They were never such devices in the first place
No, I meant they would return false data instead of an error. Used to be you never got corruption, just success or fail. Now you have success, false success, or fail.
Are you really? "Non-recoverable Read Errors per Bits Read, Max", say Seagate - that just means it couldn't correct, not that it couldn't detect there was an error.
> are you saying they are overestimating the error rate?
Perhaps not, as a general order-of-magnitude upper-bound on a marginal drive in poor conditions, but certainly if you're interpreting it as an average. Too many people would be seeing it happen way too often to keep quiet about it otherwise.
> Used to be you never got corruption, just success or fail
If this were the case, forums would be filled to the brim with ZFS users whinging about how they get CKSUM errors practically every time they scrubbed their pools. They do happen, but nothing like that frequently.
> That means hard disks can no longer be considered reliable devices that return the data written to them
They were never such devices in the first place if you ever valued your data enough to care. Even if your disks are perfect, your cabling, backplanes, IO controllers, drivers or memory probably aren't.