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The 8Tb WD SMR drives I have use a 40gb chunk of the surface for non-SMR reads and writes as a buffer. Altering anything in an SMR track requires copying the d
by timschmidt 2y ago
The 8Tb WD SMR drives I have use a 40gb chunk of the surface for non-SMR reads and writes as a buffer. Altering anything in an SMR track requires copying the data from that track and tracks near it into the buffer, then laying them back down into the SMR region sequentially. Like erasing a flash block before writing. Unfortunately, this means that the drive's performance takes a dump from 200mb/s down to 300kb/s if you do enough transfers to fill the 40gb buffer, or attempt multiple transfers at once.
- 01HNNWZ0MV43FF 2y agoI sure hope it honors fsync!
- AlexandrB 2y agoNot sure, but interestingly SMR drives support TRIM commands: https://superuser.com/questions/1407990/what-does-trim-on-an-hdd-mean https://superuser.com/questions/1407990/what-does-trim-on-an...
- matrix_overload 2y agoThey still have valid use cases like backups or unedited video footage. It's just kinda lame that the manufacturers don't market them as "slow backup devices" clearly listing all limitations, and that you have to find it out first time you use it.
- timschmidt 2y agoWhen I have used them for backups, the 40gb buffer quickly fills and then I'm stuck with speeds slower than my internet connection until the buffer empties, which it will only do if I kill the existing transfer. SSDs can dump 40gb of data very quickly. Annoyingly, since the r/w head has to do it's back-and-forth dance between the buffer area and the SMR areas, this condition even impacts read speeds. Consequently I wouldn't even use them for backups. Nor would I buy them again. I've set them up as Storj drives, which they seem to handle reasonably, and I am thankful to be done with them otherwise. If you're considering one, I would pay special attention to the buffer size, and ensure that all the transfers you want to do to or from the drive are significantly smaller than the buffer to ensure reasonable performance. That excludes most video too. Storj files are typically just a few megabytes, and typically arrive at a frequency of just one or two per second, which the drive can handle.
- matrix_overload 2y agoI had that problem as well (8TB Seagate). It would write some data, then get completely stuck to the point where Windows would report an I/O error. So I wrote a small tool that writes data in smaller chunks, monitors the write speed and allows throttling it if needed. Weirdly enough, just using the tool instead of copying files with Explorer somehow stopped the weird hanging from happening, even without having to enable the actual throttling. Probably some bug somewhere along the driver/firmware stack triggered by the write block sizes. Overall, I wish the drive vendors would expose some API to directly manage the SMR/CMR areas via software, just like the FLASH memory chips do. That would make the job of appending new backups + overwriting the old ones actually manageable with predictable and consistent timing.
- timschmidt 2y agoIt also seems like a potential opportunity for hybrid flash hard drives, where the flash could take over the role of the CMR buffer region and reduce the amount of back-and-forth required of the drive's rw head, which should considerably increase performance.
- WithinReason 2y agoThis could even happen is SW with separate drives.
- mrkstu 2y agoI assume Apple’s ‘Fusion’ drive tech is still active in their OS for backwards compatibility. It’d be interesting to try it on one of these drives.
- wtallis 2y ago> Overall, I wish the drive vendors would expose some API to directly manage the SMR/CMR areas via software, just like the FLASH memory chips do. They do, on drive models that are sold to the customers large enough to have the resources to re-write their storage stack to handle zoned block devices. The drives sold at retail will continue to pretend to be ordinary random-access block devices for the sake of backwards compatibility.
- kstrauser 2y agoI stopped buying WD after they slapped the Red label on their SMR drives. I’m sure there are good uses for them, but being a member of a RAID ain’t one.
- nirav72 2y agoFor low usage like on a NAS ,they are fine for me because they usually last me about 5 years. Maybe more if I don’t replace them for larger versions. They’re about $50 cheaper than other better performing models. They’ve also outlasted every seagate drive I’ve had in the same size and price category. Of course I would never use them for anything other than a NAS.
- bb88 2y agoFor low speed writes -- e.g. trying to download things over the internet say and then save them off, but not for trying to backup multi terabyte data to it. If they increased the size to 4TB say, to make it easier to import data to it, it might be worth it. But if it takes several days to write 32GB of data to it, it's not really gonna be worth it to most people. I've wondered why WD/Seagate don't invest in a consumer solution where drives are literally just plug and play together and give you raid without the hassle of a raid controller or software. Eg. An 8TB drive connected to an 8TB drive is a mirrored raid. SMR drives would serve as "cold storage". Once written to, would never be rewritten again.
- hypercube33 2y agoThat'd be a leap from USB/SATA/sas native chips to a full blown nix os with a microcontroller and secondary bus on it to handle drive to drive. if you want that I think they do have in box solutions with two or more drives and a while back sold their own NAS drive system. Not sure what they have today but there are plenty of free or free enough solutions out there these days.
- timschmidt 2y agoFYI all modern hard drives have multi-core ARM or Risc-V microprocessors built-in. Usually one core manages the motor control and signal decode from the RW head and another core runs an embedded OS and manages the data interface to the host computer. Folks have managed to get malware running on the hard drive's embedded CPU(s)[0] as well as full blown Linux distributions [1]. So your average hard drive definitely already has enough grunt to get the job done. Just needs a firmware written to expose the functionality. 0: https://hackaday.com/2015/06/08/hard-drive-rootkit-is-frighteningly-persistent/ https://hackaday.com/2015/06/08/hard-drive-rootkit-is-fright... 1: https://spritesmods.com/?art=hddhack https://spritesmods.com/?art=hddhack
- jauntywundrkind 2y agoGiven that 40GB is like $6 of ssd, it wouldn't be hard to provide an actual useful SSD buffer. I got a Lenovo laptop for the parents a long time ago that had a hybrid hard drive; I think maybe 8 or 16GB builtin SSD. Man that thing was just absolute trash, so slow; ghastly long boot times or time to launch a browser. Ideally a SMR drive has a SMR capable file-system, where it can write data into linear logs & them try to batch rewrite the metadata. Even the pathologically terrible random writes can be somewhat coped with via accommodating fs.
- wtallis 2y agoOne flash chip isn't going to get you a buffer with higher throughput than a hard drive. It just gives you lower latency.
- wmf 2y agoAn 8-channel SSD can do over 10 GB/s so... no? A single flash channel should give 1 GB/s or more.
- wtallis 2y agoThe SSDs that go that fast also have multiple dies per channel. And write speed is the relevant metric here, but SLC caching isn't useful unless you have flash capacity to spare.
- userbinator 2y agoAny flash being used as a cache for a HDD had better be SLC, and even then it introduces a longevity problem. Perhaps a good use for Optane.
- WantonQuantum 2y agoI have a Seagate 8Tb SMR drive that I use for movie rips from my Blu-rays. In Australia "format shifting" is allowed if you keep the original format. Linear writing and reading of 30Gb files is a great use case for it. Edit: Actually I think we now have an equivalent of the DMCA so breaking the encryption on the Blu-ray would be infringing that. Oh well.
- PostOnce 2y agoIf you're not "allowed" to watch a movie you paid for on a TV you paid for, something is deeply wrong with the law.