I’m wondering if we’re living on the same planet as these people. They literally put NAS in the name of the drive??

Does NAS drive arrays exist outside of a RAID? Is there such a thing in consumer, prosumer, or professional setups?

Single-drive NAS exists. Apple's now-discontinued Time Capsule is probably the most famous example.

That true, but isn't exactly the most common use-case, though, or what most people would assume.

WD's actions are still inexcusable, especially because the non-SMR and SMR models cost pretty much the same. No savings being passed on to us. Pure greed.

Yep, though they are actually advertised as being for RAID, not just NAS (though NAS is in the name)

Yes. Take a look at UnRaid. It’s essentially a drive array with some number of parity drives (like a RAID), but no striping of files across drives.

There's plenty of cheap drives sold as NAS drives which have no RAID, or enclosures which default to JBOD, so their suggestion seems to be that the standard Red drives are now only suitable for "Build your own MyBook" use.

THis is in NO WAY a defense of WD, just an awnser to the question "Does NAS drive arrays exist outside of a RAID?"

RAID has several levels.. Any RAID that uses Parity will have a problem with SMR, but Mirror and Striped array probally will not

A common use case is a 2 Disk Mirror NAS for SMB.

Further NAS manufactures like QNap, and even WD do make single disk NAS Appliances

However the WD Red line is branded for NAS upto 8 drives, Most likly that will be a RAID5 or 6 array making SMR not usable in that configuration

My understanding is that SMR drives fail because the write load is continuous for a long period of time and overwhelms the background process organizing the data for efficient SMR writes. In a 2-disk mirror (RAID1) rebuild, all data from one drive has to be copied to the other drive, which seems likely to overwhelm an SMR drive. So it would seem to only work in a RAID0 array (concatenated drives - bad idea) or JBOD NAS setup.