Toshiba, Seagate shipping slower SMR drives without disclosure, too • Hacker News Board

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#41

Post by otterley » Sat, Apr 18, 2020, 5:03 PM UTC

Exmoor wrote: post #28

jasonlingx wrote: post #21

If customers cared enough, wouldn’t someone just market their drives as PMR and this would solve itself? It would make sense to have a lower cost alternative that would fulfil most consumer needs though.

I can't speak for the drives mentioned in this article, but the WD Red drives were de facto marketed as PMR since the Red line was marketed by WD as the best drives for NAS. It'd be a little like if you went down to the your local Ferrari dealership and bought a Ferrari only to find that they'd started selling a model that couldn't reach 60mph.

> WD Red drives were de facto marketed as PMR

Do you have a reference? Or any evidence of customers knowing or caring about the internals of the drive before this controversy arose?

Claiming that anything is the "best" at something is pure puffery, as we say in the legal trade. Ferrari publishes quantifiable specs on how their vehicles perform; WD does not do so in detail.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#42

Post by loeg » Sat, Apr 18, 2020, 5:16 PM UTC

toast0 wrote: post #33

LeifCarrotson wrote: post #15

Is there any way small-scale ~4 drive NAS or file server systems can accommodate SMR drives in software? It looks like they're going to need to do so...

It would really be best if the drive properly identified itself, so the host os/filesystem could adapt to the drive parameters. That said, you would want to use a log structured filesystem, with a compaction feature. You want to avoid read-modify-write on the shingled areas, it's time intesive and competes with other I/O.

You don't need a single Log structure -- the shingle stripes are on the order of 128 MB of or so. Any CoW filesystem can relatively easily adapt to this kind of system; in-place filesystems are basically boned on SMR. The CoW filesystem aren't going to be fast on SMR, mind you, just not quite as awful.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#43

Post by loeg » Sat, Apr 18, 2020, 5:19 PM UTC

Wowfunhappy wrote: post #40

MrBuddyCasino wrote: post #39

Earlier quoted context omitted.

HGST still has a good reputation, due to top backblaze stats.

They were bought by WD a few years back.

2012 in fact. I thought it was much more recent, myself.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#44

Post by dragontamer » Sat, Apr 18, 2020, 5:22 PM UTC

canada_dry wrote: post #24

Adding to this confusing debacle is how HDDs are now being marketed like running shoes: one type for running, one for squash, one for tennis, one for basketball...

There are only maybe... 3 or 4 elements of HDD designs worth talking about.

* CMR/PMR drives -- Classic hard drive you've been buying for the last 30 years. Not much to say about it.

* SMR Drives -- "Shingled" has very poor write performance, but adds 20% more capacity at lower costs. For "write once, read many" workloads, like archival or backups. This is because "Shingled" drives write data on top of the old data, so that your data is physically overlapping at the microscopic level. Any write must read the old data, rewrite the old data, and then finally write the new data you're planning to store.

* 5400 RPM vs 7200 RPM -- Higher RPM drives are obsolete, because SSDs are faster. 7200 RPM is kind of standard, but 5400 exists for those who want less noise, less electricity usage, and are willing to put up with the lower performance.

That's pretty much it. "NAS" drives tend to have anti-vibration sensors and other such things, but those sensors don't really cost much and I don't really see why it deserves its own category.

-------------

There only needs to be maybe, 3 kinds of hard drives made today. 7200 PMR drives, 5400 PMR drives, and finally 5400 SMR drives.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#45

Post by dragontamer » Sat, Apr 18, 2020, 5:28 PM UTC

MrBuddyCasino wrote: post #39

aasasd wrote: post #5

Is there a trusted hdd manufacturer left? I'd like to not spend several weeks on research when I again get the urge to rebuild the NAS.

HGST still has a good reputation, due to top backblaze stats.

HGST was bought by WD, and then parts of it were forcibly sold off to Toshiba for anti-trust reasons.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#46

Post by seized » Sat, Apr 18, 2020, 5:30 PM UTC

loeg wrote: post #42

toast0 wrote: post #33

Earlier quoted context omitted.

It would really be best if the drive properly identified itself, so the host os/filesystem could adapt to the drive parameters. That said, you would want to use a log structured filesystem, with a compaction feature. You want to avoid read-modify-write on the shingled areas, it's time intesive and competes with other I/O.

You don't need a single Log structure -- the shingle stripes are on the order of 128 MB of or so. Any CoW filesystem can relatively easily adapt to this kind of system; in-place filesystems are basically boned on SMR. The CoW filesystem aren't going to be fast on SMR, mind you, just not quite as awful.

Except filesystems like ZFS are having issues on these SMR Reds during resilvers (rebuilds) because SMR slows down so much.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#47

Post by baybal2 » Sat, Apr 18, 2020, 5:30 PM UTC

DeathArrow wrote: post #10

Trying to pass SMR as PMR is kind of pointless since HDD becomes more and more pro and enterprise territory and consumer are shifting away to SSD. Their customers are increasingly likely to be the kind of people who care about this kind of thing.

> pro and enterprise territory

This doesn't change the fact that enterprise customers are equally screwed by DMSMR drives.

Adding insult to injury is that those disguised SMR (DMSMR) drives were made with very intention to sell "unsalable" SMR drives to Windows users.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#48

Post by dragontamer » Sat, Apr 18, 2020, 5:31 PM UTC

otterley wrote: post #30

Are the disk vendors publishing performance metrics that are being violated by the use of SMR technology? Or is this just one of those cases of performance generally not being as good as it used to be, and customers becoming reliant on past behavior despite the lack of an explicit performance promise from the vendors?

> Are the disk vendors publishing performance metrics that are being violated by the use of SMR technology?

Not really, no. SMR drives overlays data on top of each other, like "shingles" on a typical American roof.

As such, whenever an SMR drive writes data, it must read the data "underneath" the current spot, rewrite the "underneath" data, and then lay the new data on top of it.

SMR drives are great for archives (write once, read many). But they're pretty much useless to the typical consumer. SMR drives should be avoided if you're building your own computer.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#49

Post by dragontamer » Sat, Apr 18, 2020, 5:33 PM UTC

otterley wrote: post #41

Exmoor wrote: post #28

Earlier quoted context omitted.

I can't speak for the drives mentioned in this article, but the WD Red drives were de facto marketed as PMR since the Red line was marketed by WD as the best drives for NAS. It'd be a little like if you went down to the your local Ferrari dealership and bought a Ferrari only to find that they'd started selling a model that couldn't reach 60mph.

> WD Red drives were de facto marketed as PMR Do you have a reference? Or any evidence of customers knowing or caring about the internals of the drive before this controversy arose? Claiming that anything is the "best" at something is pure puffery, as we say in the legal trade. Ferrari publishes quantifiable specs on how their vehicles perform; WD does not do so in detail.

SMR is terrible for NAS setups, particularly RAID5. Absolutely terrible. Under no circumstances should you be putting an SMR drive into your NAS.

Re: Toshiba, Seagate shipping slower SMR drives without disclosure, too

#50

Post by baybal2 » Sat, Apr 18, 2020, 5:49 PM UTC

LeifCarrotson wrote: post #15

Is there any way small-scale ~4 drive NAS or file server systems can accommodate SMR drives in software? It looks like they're going to need to do so...

> Is there any way small-scale ~4 drive NAS or file server systems can accommodate SMR drives in software? It looks like they're going to need to do so...

The thing is you can't really buy SMR disks that are OS controlled unless you are some big enterprise client.

SMR disks discussed here are DM-SMR disks, which basically are same disks, but with a firmware based hack that makes them appear as regular SATA disks.