So weird! Tech companies being deceitful! Never happens. Glad it is only the P series of the Toshiba drives. I would hate to have a reason to not like my X300 series drives. They have been great.
Shingled magnetic recording (SMR) is a magnetic storage data recording technology used in hard disk drives (HDDs) to increase storage density and overall per-drive storage capacity.[1] Conventional hard disk drives record data by writing non-overlapping magnetic tracks parallel to each other (perpendicular recording), while shingled recording writes new tracks that overlap part of the previously written magnetic track, leaving the previous track narrower and allowing for higher track density. Thus, the tracks partially overlap similar to roof shingles. This approach was selected because physical limitations prevent recording magnetic heads from having the same width as reading heads, leaving recording heads wider.[2][3][4]:7–9
The overlapping-tracks architecture complicates the writing process since writing to one track also overwrites an adjacent track. If adjacent tracks contain valid data, they must be rewritten as well. Device-managed SMR devices hide this complexity by managing it in the firmware, presenting an interface like any other hard disk. Other SMR devices are host-managed and depend on the operating system to know how to handle the drive, and only write sequentially to certain regions of the drive.[4]:11 ff.[5]
Seagate has been shipping device-managed SMR hard drives since September 2013, while referring to an increase in overall hard disk drive capacity of about 25%, compared to non-shingled storage.[1] In September 2014, HGST announced a 10 TB drive filled with helium that uses host-managed shingled magnetic recording,[6] although in December 2015 it followed this with a 10 TB helium-filled drive that uses conventional non-shingled perpendicular recording.[7] In November 2018, HGST introduced 14- and 15-TB drives.[8]Western Digital, Seagate and Toshiba have begun selling SMR drives without labeling them as such.[9]
Data management
There are three different ways that data can be managed on an SMR drive:[10][11]
Device Managed
Host Managed
Host Aware
Device managed
A Device Managed drive appears to the host identically to a non-shingled drive. It is not necessary for the host to follow any special protocols. All handling of data, as it relates to the shingled nature of the storage, is managed by the device. In addition, the host is unaware that the storage is shingled.[4]
Host managed
A Host Managed device requires strict adherence to a special protocol by the host. Since the host manages the shingled nature of the storage, it is required to write sequentially so as to not destroy existing data. The drive will refuse to execute commands which violate this protocol.[4]
Host aware
Host Aware is a combination of Drive Managed and Host Managed. The drive is capable of managing the shingled nature of the storage and will execute any command the host gives it, regardless of if it is sequential or not. However, the host is aware that the drive is shingled, and able to query the drive for fill levels. This allows the host to optimize writes for the shingled nature, while also allowing the drive to be flexible and backwards-compatible.[4]
Dynamic hybrid SMR
While for traditional SMR models each zone is assigned a type at manufacture time, dynamic hybrid SMR drives allow to reconfigure the zone type from shingled to conventional and back by the customer.[12][13]
WD issued a statement today where they clarified which drives use SMR. It appears that their undisclosed use of SMR was pretty limited, though one can see where the WD Red 2-6TB, a very common size range for use in NAS's would be problematic. The $50 price difference between the Red and Red Pro 6TB drives likely shows exactly why they use SMR, though the Red Pro is 7200RPM.
