Western Digital Continues Working On SMR / Zoned Device Support For Btrfs

[starshipeleven]

It would make sense to go back to days of having platters separated from the mechanism.

No it would not.

If you want to see how it is the world of "having platters separated from the mechanism" you can look at the DVD/Bluray/whatever world.

[starshipeleven]

So what are these new commands? What does Zoned mean?

It's useful only for SMR hard drives.

[Adarion]

Worries me that a FS has to be aware about the very nature of the storage HW, I'd rather like that to be transparent. Either way, SMR _is_ slow as soon as you have to re-write overlapping sectors. (One can find that info on every corner in the net.) The achieved storage capacities might be impressive, but this is only good as a WORM media for archival purposes.

[torsionbar28]

SMR is only slower for random IO, not a big linear copy.

Single big linear copy is really the only use case for these SMR drives. They're terrible at everything else. SMR is essentially a tape drive replacement, not a hard drive replacement. Anyone using SMR drives in a random I/O scenario (i.e. desktop or server workloads) is doing it wrong.

I do own a few SMR drives myself, and I use them exclusively for periodic backups (i.e. what would otherwise be done with tape) and they work great in this scenario.

[torsionbar28]

Or if you're Netflix and you're serving petabytes of static data that is being read but not written to.

[tg--]

Worries me that a FS has to be aware about the very nature of the storage HW, I'd rather like that to be transparent. Either way, SMR _is_ slow as soon as you have to re-write overlapping sectors. (One can find that info on every corner in the net.) The achieved storage capacities might be impressive, but this is only good as a WORM media for archival purposes.

Filesystems already have some awareness to the hardware - and had this since forever.
Historically you could just assume that your storage was a standard hard-disk, and that's what most standard-filesystem authors did.
Today we have SSD-aware scheduling, TRIM, queues, ...

SMR drives are clearly no WORM drives. They are absolutely acceptable for regular use. They are just not very fast.
But they bring huge capacities in small formfactors and are reasonably cheap.

They are basically the equivalent of Triple-Level-Cell SSDs. Those are also a lot slower than MLC or SLC, but still perfectly acceptable and much cheaper.

Everything is a trade-off in tech.

[Guest]

No it would not.

If you want to see how it is the world of "having platters separated from the mechanism" you can look at the DVD/Bluray/whatever world.

Optical disks aren't really made for enterprise usage, and there are other ways to store data on disks. I think having a niche format would be nice.

[torsionbar28]

Optical disks aren't really made for enterprise usage, and there are other ways to store data on disks. I think having a niche format would be nice.

Not true. Magneto Optical (MO) drives are made specifically for enterprise usage. This is the niche format you're looking for. While its heyday in the US was a while back, it's still actively manufactured and used in Japan today. The claim to fame for MO, is very long data retention. IIRC something like 100 years is claimed. It can still be found in active use, in certain corners of the medical and legal communities in the US. Performance of MO media and drives was never amazing, but that's not their purpose.

[starshipeleven]

Optical disks aren't really made for enterprise usage, and there are other ways to store data on disks. I think having a niche format would be nice.

Lol no. Some disks tried to target enterprise usage, and at least 2-3 technologies could claim they were more rugged and could outlast hard drives. None remembers them anymore. They simply could not keep up with hard drive capacity increases.

Only tape drives kept struggling though while still slowly losing ground, but it is very shitty technology and should really die in a fire.


My point here is that without integrating the read/write system with the medium you are significantly slowing down the capacity increase of your media over time.

Hard drive controllers are tuned to the specific hard drive model/design they are working in, and this allowed significantly faster development and turnover than a dumb disk standard where you can't expect people to buy a new reader for each new minor revision of disks.

[Guest]

Not true. Magneto Optical (MO) drives are made specifically for enterprise usage. This is the niche format you're looking for. While its heyday in the US was a while back, it's still actively manufactured and used in Japan today. The claim to fame for MO, is very long data retention. IIRC something like 100 years is claimed. It can still be found in active use, in certain corners of the medical and legal communities in the US. Performance of MO media and drives was never amazing, but that's not their purpose.

MO and consumer-grade optical disks are completely different things.