- Nov 10, 2017
Without bad publicity, WD would not change a thing. Now I hope they clarify their communication about SMR, and best case this publicity leads to innovation to improve SMR performance for future drives. When WD accomplishes that, they are encouraged to communicate and celebrate that of course
Very good. The fact that Western Digital reversed itself with this disclosure indicates a tacit acknowledgement that this is simply the right thing to do. I forgive 'em.
- At least one of the WD Red DM-SMR models (the 4TB WD40EFAX with firmware rev 82.00A82) does have a ZFS compatibility issue which can cause it to enter a faulty state under heavy write loads, including resilvering. This was confirmed in our labs this week during testing, causing this drive model to be disqualified from our products. We expect that the other WD Red DM-SMR drives with the same firmware will have the same issue, but testing is still ongoing to validate that assumption.
- In the faulty state, the WD Red DM-SMR drive returns IDNF errors, becomes unusable, and is treated as a drive failure by ZFS. In this state, data on that drive can be lost. Data within a vdev or pool can be lost if multiple drives fail.
AS LONG AS the drive makers publish the essential performance and warranty specs (which they do), why does it matter?
Law firm Hattis & Lukacs has filed an amendment to its class-action lawsuit against Western Digital for including SMR technology in its WD Red line of NAS drives. The amendment adds five more named plaintiffs from five new states, and it includes significant additional technical detail.
If you aren't up to date on the SMR saga, this is one article in an ongoing series. The short version: SMR—Shingled Magnetic Recording—is a relatively new hard drive recording technology that allows higher data densities. It does so by laying down overlapping tracks—like shingles on a roof—with a write head that's wider than the read head. Unfortunately, this technology makes rewriting existing disk sectors agonizingly slow in many cases—rewriting a single 4KiB sector will generally mean needing to both read and rewrite an entire 256MiB zone. The original American class-action suit (there's a Canadian one as well) had a single named plaintiff, Wisconsin's Nicholas Malone. The amendment features five new plaintiffs, each from a different state, and tells each plaintiff's story in detail.
WD's announcement outlines a new series of WD Red Plus drives that come with the standard CMR technology, but in the same 2 to 6TB capacity points as the slower SMR drives. WD positions the new Red Plus drives for its customers with more demanding needs, particularly in the SOHO and SMB segment, that need better performance with ZFS RAID arrays.
WD will continue shipping the 2 to 6TB WD Red drives with DM-SMR (Drive-Managed SMR) for less-demanding SOHO users, with the existing CMR WD Red drives being moved to the WD Red Plus line to create a split product stack. The WD Red Pro line remains unchanged with CMR drives.
WD has started listing its existing hard drives with SMR technology in marketing materials, and retailers have updated product listings. For some impacted customers, the company is also replacing SMR drives with faster CMS models. Still, WD will have to be clear with the new drive positioning to avoid confusion among less tech-savvy customers that could seek out the WD Red family as a value alternative while not fully understanding SMR's impact on performance.