News emerged earlier this week that Western Digital was producing NAS hard drives using SMR technology -- which results in slower performance in some types of applications -- without disclosing that fact to customers in marketing materials or specification sheets. After a bit of continued prodding, storage industry sage Chris Mellor secured statements from both Seagate and Toshiba that confirmed that those companies, too, are selling drives using the slow SMR technology without informing their customers. The latter two even use the tech in hard drives destined for desktop PCs. //

It's important to understand that there are different methods of recording data to a hard drive, and of the productized methods, shingled magnetic recording (SMR) is by far the slowest. //

As such, these drives are mainly intended for write-once-read-many (WORM) applications, like archival and cold data storage, and certainly not as boot drives for mainstream PC users. //

the industry developed SMR to boost hard drive capacity within the same footprint. The tactic revolves around writing data tracks over one another in a 'shingled' arrangement. //

For WD, that consisted of working the SMR models into its WD Red line of drives, but only the lower-capacity 2TB to 6TB models. Slower SMR drives do make some measure of sense in this type of application, provided the NAS is used for bulk data storage. Still, compatibility issues have cropped up in RAID and ZFS applications that users have attributed to the unique performance characteristics of the drives.

Toshiba tells Block and Files that it is also selling SMR drives without listing them on spec sheets, but does so within its P300 series of desktop drives. Seagate also disclosed that it uses the tech in four models, including its Desktop HDD 5TB, without advertising that fact. However, Seagate, like others, does correctly label several of their archival hard drives as using SMR tech, making the lack of disclosure on mainstream models a bit puzzling.