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Toshiba, Seagate shipping slower SMR drives without disclosure, too

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

#121

Post by wtallis »

ZWoz wrote: post #117
dragontamer wrote: post #44

Earlier quoted context omitted.

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,…

10 000 RPM SAS drives absolutely still exists and are relevant. I got my last batch 2 months ago or so. Those SAS drives have nice capacity (2,4TB) and you don't need to worry about DWPD.

What kind of workload do you have where there are enough writes that a 1+ DWPD SSD isn't viable but the performance of a 10k RPM hard drive is adequate?

It would have to be a highly sequential workload for hard drive performance to not be a problem, but that means it's also a workload that's well-suited for QLC SSDs that are cheaper per GB up front and draw less than half the power and are faster in every way. If your worries about write endurance are at all realistic, you must be averaging upwards of 50MB/s of writes over the entire lifespan of the drive, meaning your hard drives are spending at least 20% of their service life actively writing data.

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

#122

Post by wtallis »

dragontamer wrote: post #105
lopmotr wrote: post #100

Earlier quoted context omitted.

How do "surveillance" drives fit into that? They're supposed to be special for being reliable with a lot of writing, several orders or magnitude more the drive's capacity. Apparently normal hard drives aren't reliable enough for recording CCTV footage.

All hard drives have effectively infinite rewrite capability, unlike SSDs. I know I've seen surveillance drives before (WD Purple), but I never figured out what made them special compared to others. Looking at the WD Purple drive marketing material... they describe "support for 64 cameras". Which means the CCTV community is willing to pay for write bandwidth. It'd probably be a standard 7200 PMR drive, but with assur…

I've heard WD allude to their surveillance drives having some kind of firmware optimizations to handle multiple streams of writes with good QoS. It seems plausible they they would have a bit of a different write caching strategy based on minimizing seeks and trusting that the data coming into the drive is interleaved from multiple sequential write streams even though at any given moment the command queue will look like a bunch of random writes.

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

#123

Post by wtallis »

marcan_42 wrote: post #103
Nursie wrote: post #29

Earlier quoted context omitted.

QLC with a decent SLC cache seems to work just fine as well, for most consumer purposes - see drives like the sabrent Rocket-Q

QLC with an SLC cache is the SSD equivalent of SMR. They are fine for read-mostly workloads but performance goes completely down the drain when you do random writes. I've tried QLC drives for cheap cluster storage. It turns out one QLC drive was slower than 4 old HDDs. I had to go back to HDDs until I switched to TLC flash because they were faster. Tail latencies hitting one second on QLC. It's incredible how bad the…

> It turns out one QLC drive was slower than 4 old HDDs.

Was that a consumer QLC drive with SLC cache or an enterprise QLC drive with no cache and firmware that actually cares about latency? Something like the Micron 5210 ION enterprise QLC drive should still have at least 20x the sustained random write performance of a single hard drive.

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

#124

Post by fomine3 »

dragontamer wrote: post #49
otterley wrote: post #41

Earlier quoted context omitted.

> 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.

The worst thing that WD done is adopting SMR on NAS brand without announce. SMR for parity RAID is completely disaster. Adopting SMR on Desktop brand is acceptable compared to NAS brand, but it should be announced.

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

#125

Post by fomine3 »

dragontamer wrote: post #44
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,…

IIRC, PMR(perpendicular magnetic recording) technology is also used on SMR drives, so It's not correct term to differentiate SMR. And the technology have been used around 15 years.

CMR(conventional magnetic recording) is retronym to differentiate SMR.

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

#126

Post by def8cefe »

aasasd wrote: post #107
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...

I just have to know: which HDD for tennis?

2.5" PATA, more economical and less accidental head trauma.

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

#127

Post by loeg »

Dylan16807 wrote: post #104
loeg wrote: post #102

Earlier quoted context omitted.

You'd need a filesystem that was pretty careful to write a very large chunk extremely sequeuntially. That's easiest with Host-aware SMR (to have some idea the size of the zones) or a linear LogFS.

Yes, I agree entirely. But the point I'm making is that "host-aware" should be good enough for this type of use. Even though it's still drive- managed , the internal logic in the drive should pass through certain write patterns without interference. And you can make the host aware through feeding in a few parameters; it doesn't necessarily have to interrogate the drive. In other words, I'm disagreeing with the idea t…

Ah, maybe. It’s not a big step from aware to managed, though. The zoned api is actually quite simple: what are the zones?, open zone, finish zone. The filesystem that’s tolerant of these characteristics is the hard part.

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

#128

Post by Dylan16807 »

loeg wrote: post #127
Dylan16807 wrote: post #104

Earlier quoted context omitted.

Yes, I agree entirely. But the point I'm making is that "host-aware" should be good enough for this type of use. Even though it's still drive- managed , the internal logic in the drive should pass through certain write patterns without interference. And you can make the host aware through feeding in a few parameters; it doesn't necessarily have to interrogate the drive. In other words, I'm disagreeing with the idea t…

Ah, maybe. It’s not a big step from aware to managed, though. The zoned api is actually quite simple: what are the zones?, open zone, finish zone. The filesystem that’s tolerant of these characteristics is the hard part.

It's a big step in terms of product segmentation. You don't want to sell a drive that just fails to work in most machines.

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

#129

Post by cthalupa »

otterley wrote: post #75
cthalupa wrote: post #63

Earlier quoted context omitted.

Try to do a resilver with SMR drives. I just got fucked by this change in models - I had an array full of 6TB WD Reds, had one fail, ordered a replacement. Rebuilding the RAID-Z3 took over 2 weeks. Previous replacements had taken under 2 days - usually under 1. Passing SMR drives off without saying anything, especially when that exact model had been a PMR drive prior, is incredibly anti-customer.

The model number did change. The older drive was a WD60EFRX; the newer SMR drive is a WD60EFAX. Am I mistaken?

WDC_WD60EFRX-68L0BN1 vs WDC-WD60AFA-68SHWN0

Do you believe it is reasonable for customers to see this and expect that a drive called "WD 6TB Red" when you purchased previously and when you go to purchase it now, that are described identically, with no way to purchase the previous model, and know that the fundamentals of the storage medium have changed and completely flip it's performance characteristics?

Especially when the drive is specifically marketed as being RAID and NAS friendly - one of the primary differences between the Red and Green drives is disabling some of the sleep power saving mechanisms that are known to cause issues with RAID arrays. And they make it so that the drive is largely unusable in any parity based array? When minor revisions, updated firmware, etc., will result in minor changes to model numbers all the time?

Because, well, I don't.

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

#130

Post by jyrkesh »

dragontamer wrote: post #44
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,…

Can you confidently confirm or cite a source that 7200 SMR doesn't exist? It doesn't sound like I can avoid buying from a sleazy company, but I at least want to avoid this SMR nightmare for a new 8-bay NAS build I was planning right up until all this broke.
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