Review on 🔒 Reliable Performance: Western Digital 4TB WD Red SMR NAS Internal Hard Drive - 5400 RPM, SATA 6 Gb/s, 256MB Cache, 3.5" - WD40EFAX by Dennis Wood

It has very poor overwrite performance. Especially if you are using this in a ZFS RAID these drives will likely be removed. In comparison, RAID recovery can take a long time. These drives are generally considered unsuitable for NAS and should not be labeled as such. The bigger problem is that Western Digital (Seagage and Toshiba are also on board) has been building new drives using this cheaper technology without passing on the customer's savings or warning the customer about a performance hit. Search something like "SMR WD Red" for good information on the subject.