 On May 29th, 2020, Hattis Law filed a class action lawsuit against Western Digital, accusing the company of secretly selling hard drives built with SMR technology. And no, the problem wasn't that these hard drives were whispering, neck tingling sweet nothings into their users' ears. It's that SMR not only makes the drives slower, but in some cases, completely unusable for their marketed purpose. Here's the thing, even though Judge Judy is everything I aspire to be, normally we don't delve into companies getting sued on this channel. But for this lawsuit, I'm making an exception for two reasons. One, because Patrick from Serve the Home asked me to, and he's just a super nice guy. And two, because the reasons that this whole thing is happening, and what it means for the industry, and for you, are super interesting and super techie. And today's video was brought to you by GlassWire. Keep track of the weird stuff that's connecting to your PC, even when you aren't using it, with GlassWire. You can see if a strange device joins your Wi-Fi and block it instantly. Get 25% off today using code Linus at the link below. [♪ music playing and title screen music playing. SMR stands for Shingled Magnetic Recording, and it's a relatively new technology in the world of hard drives, having just entered the market in 2014. Now as you may know, inside a hard drive are magnetic actuator arms that read and write data to a set of spinning platters. Now in Perpendicular Magnetic Recording, or PMR, which is also known as Conventional Magnetic Recording, or CMR, those platters have single tracks laid out side by side. This makes each track easy to access by the read and write arms, but capacity is limited to how many tracks you can squeeze next to each other on a single platter. In Shingled Magnetic Recording, or SMR, platters are made up of chunks of overlapping tracks, kind of like the shingles on a roof. This technique allows more tracks to fit onto a single platter, increasing capacity, but it comes at a cost. You see, each time a new track is written, it overlaps part of a previously written track, which must then also be rewritten. I mean, it sounds kind of insane, doesn't it? I mean, imagine a word processor where every time you wanted to change a word in a paragraph, you had to go back and rewrite the rest of the paragraph along with your changes. Terrible. I mean, that experience, not lttstore.com. lttstore.com is great. Great products. But anyway, for hard drives, this approach is actually very sane. You see, SSDs kind of have the whole speed thing on lock these days. So most hard drive innovation over the last few years has been pretty focused on capacity, and Shingled Magnetic Recording allows drive manufacturers to exchange a bit of performance for as much as 25 to 50% higher capacity per platter. That means either greater capacities or fewer platters for a given capacity, lowering the total cost. So then that's problem number one, really. Hard drive manufacturers selling a cheaper product without labeling it as such. But why are people so upset? Well, you see, it's not just that SMR drives have slower performance. It's that to work properly, they need special firmware or software that can navigate through all of these overlapping tracks. So there are three different varieties of SMR. In host-managed SMR, the host computer must give special commands to the drive. If the drive doesn't receive these commands, it simply will not work. These kinds of drives are most commonly used in cloud servers owned by, you know, Amazon or Google, where vast quantities of drives must be controlled. The second type, host-aware SMR, allows the drive to respond to these special commands or to regular commands. So you don't necessarily need special software to use that second type, but it certainly helps. The third type of SMR is where things get messy. In device-managed SMR, the drive doesn't require special commands, and in fact, it shows up in your PC as a completely normal drive. Most of the time, this isn't catastrophic. In fact, this type of SMR drive usually has a CMR cache, which can be written more quickly for a short period, masking that slower write performance. This approach is actually very similar to how many slower QLC SSDs use a high-speed SLC cache, as we discussed in this video right here. So the idea is that when you write some data to the drive, it goes into the higher speed cache, and your file transfer is complete, your data is safe, but then 20 minutes, 30 minutes later, you might actually still hear the drive thrashing away as it dumps the data out of the cache onto the slower shingled portion. For most home users, honestly, that's probably fine, and they might even be happy with the trade-off for more capacity on the cheap. But using a device-managed SMR drive when you don't know that it's an SMR drive can be catastrophic, as our good buddy Patrick found out. He and his team tested CMR drives from HGST and Seagate against two drives from WD's RED lineup, which is marketed specifically for network-attached storage systems. Only one small problem. Without clear markings, one of them was built with CMR, and the other was built with SMR. As expected, they found that the SMR drive was slower in almost every typical storage benchmark, which was bad. Then it got worse. The kicker was the Freenaz RAID-Z Rebuild. Now, RAID is designed to protect your data through redundant copies in the event of a physical drive failure. So the test involves wiping one of the drives in a RAID array intentionally and then tasking the system with rebuilding all the data that was supposed to be on it. The CMR drives all took over 16 hours, which is already a long time to be worried that your data is in this vulnerable state where if another drive dies, it could all be lost. But it is normal for this process to take a while. As for the SMR drive, it took nine and a half days! What?! Now, Patrick and co naturally thought something must be wrong with their test setup, so they ran the test again and got a similar result. Ars Technica also ran some tests, finding that in a random write latency test, the WD-RED SMR drive could take as long as 1.3 seconds to save a meg of data compared to 0.1 seconds on the Seagate CMR drive. Now, we need to mention that Serve the Home's test server ran on Freenaz, a popular open source operating system for network-attached storage. And while SMR drives have clearly been operating without disastrous consequences on other types of servers, Freenaz uses the ZFS file system, which can also be found in a ton of other software, from Ubuntu and Proxmox to NAS systems from QNAP. And apparently ZFS, according to Patrick's tests, does not play nicely with shingled magnetic recording. Now, there's some indication that SMR might cause problems for other file systems too, since Synology has listed WD's SMR drives as incompatible with a huge swath of their NAS systems, but we don't have the specifics on those ones. Anyway, all of this would have been fine if customers were educated properly so they didn't accidentally end up with SMR drives. Except as we said before, WD didn't label their SMR drives. The only indication that a given drive was SMR or CMR was a single letter in the model number. And because these drives are device-managed, the end user wouldn't even realize what they had purchased when they plugged it into their system. Now, to be fair to WD, Seagate and Toshiba also sold unlabeled SMR drives, but just not in their NAS product lines. So it was far more unlikely that those drives would lead to the type of unusable performance seen in Patrick's tests. And the good news is that all three vendors have now committed to labeling the recording technology used in their products. And to WD's credit, they seem to be responding well to customers requesting CMR replacements for their SMR drives. Meaning that the only lingering question after all this is... Why? How exactly did Western Digital, a titan of the storage industry for 50 years, miss the fact that SMR drives are completely inappropriate for ZFS, a perfectly common file system for NASes, and then market these drives for NAS use? A question that is made all the more confusing by this video from 2015, showing an engineer from HGST, a company owned by Western Digital, explaining how DMSMR has tremendous compatibility problems with ZFS and talking about how much work it would take to make them play nicely together. WD clearly should have listened to Manfred instead of evilly throwing their customers under the bus. Unless maybe something else happened here. I don't think that this is some kind of evil masterminded plot to hurt NAS users by Western Digital by any means. I think that what's more likely is that this is just a communication breakdown and process breakdown between the different functional silos within Western Digital. There's probably an element of this, which is that each person has their own personal and departmental goals aligned to their function, but not necessarily across their entire company. And what that means is that those discussions don't happen to say, hey, should we even institute DMSMR into the space? If we do, what are the tests that we need to run to make sure that it works on all of our partner systems? Personally, I like to think that best of people may be to my detriment, but having done management consulting in this space for years prior to doing STH, I can totally see how this happens. Yeah, OK. I actually made a similar argument during the Principled Technologies Benchmark scandal that Intel went through a number of months ago. And I think Patrick is probably right here as well. It's just still extremely embarrassing for them. And the class action lawsuit is absolutely, in our opinion, both good and necessary. Because normal people who bought WD-RED SMR drives may have faced a loss of time, data, and even livelihood that they wouldn't have if the product was properly labeled. And honestly, they deserve some compensation. Speaking of compensation, massive shout out to Drop.com for being our sponsor. Thanks, guys. The Massdrop and Sennheiser PC37X gaming headset features angled drivers and an open back design with drivers that come from the same family as the HD598 and HD600 series headphones. They offer great stereo imaging and locational accuracy. They sound fantastic. They're super comfortable. They come with a noise-canceling microphone, and they've sold over 45,000 of these things. So if there was a big problem with them, like if they were completely unusable for the advertised purpose, you probably would have heard about it by now. They include a two-year warranty from the manufacturer, and you can check them out at the link in the video description. If you guys enjoyed this video and you like these kinds of deeper dives into storage technology, maybe check out, oh, what was that cool when we did about tiered storage a while back? Can't remember. Hopefully you can find it. Oh, maybe just server storage. Why don't we do rolling out Nuwonic? All the issues with that. Boy, what a disaster that was. Storage, it's complicated.