In the spring, Seagate, Toshiba and Western Digital had to admit to selling unmarked hard drives that use Shingled Magnetic Recording (SMR) instead of the faster perpendicular magnetic recording (PMR) aka Conventional Magnetic Recording (CMR). However, Western Digital was the only manufacturer to explicitly advertise such models for NAS systems and still advertise them.
One blog entry Corresponding SMR variants of the WD Red are, as before, suitable for NAS systems, at least for light workloads in the SOHO segment (small office, home office). In the case of RAID configurations with a ZFS file system, Western Digital advises against the WD Red Plus or the WD Red Pro with CMR, since otherwise the NAS operation can fail due to the frequent random write processes.
Correspondingly, Western Digital published an overview of all WD-Red models with SMR and CMR. NAS manufacturers like Synology lists the SMR offshoots as incompatible, at least Qnap warns against their use. As before, Shingled Magnetic Recording is also used with other Western Digital hard drives (see PDF). However, the HDD series designated as WD Blue and WD Black are not explicitly intended for NAS systems, which is why the tracks overlapping like tiles – hence the corresponding English name – should not lead to serious problems.
WD hard drives with SMR (Image: Western Digital)
For Western Digital, the application of SMR hard drives for NAS systems could still have an aftermath, because at the end of May 2020, a class action lawsuit (PDF) filed against the manufacturer. This would have deceived and harmed consumers, which is why compensation is required. Tests like that from Serve The Homethat copying 125 GB with SMR takes two thirds longer and the RAIDZ resilver test is exorbitantly slower with around 230 hours instead of 17 hours.