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15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

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Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#111

Post by soundwave106 »

p1necone wrote: post #107
blihp wrote: post #61

Earlier quoted context omitted.

You state that with an unwarranted degree of certainty. You're making the same argument, and mistake, that proponents of 'X is going to kill hard drives' have made for decades. There have been many 'this will be the death of hard drives' technologies over the decades: zip drives, optical drives, tape drives (there was a time when they were predicted to be everywhere... never happened), CD (then DVD) writers, etc. Not…

I don't know, SSDs have already replaced HDDs in consumer systems to a far greater extent than any of the things you've listed.

Aren't most cloud computing currently almost completely HDDs at this point? At least, this is the impression that I get from looking at the case of Backblaze (which is probably the cloud storage center with the most public statistics on what they use). So far, the usage of SSDs is fairly minimal on the storage side, although I believe they are used at Backblaze some for operations such as bootup and caching. (https://www.backblaze.com/blog/hard-drive-stats-for-q1-2018/)

I would agree on consumer systems (that often have one single boot drive), SSDs make a lot of sense. These days you tend to only see HDDs at the very low end.

From a personal perspective, most of my PCs are completely SSD. But I also have a media server (the largest storage space being reserved for MKV copies of my personal DVDs and Blu Rays). This is composed of RAID arrays of 6TB HDDs. Right now, cost wise, the highest "common" SSD is 4TB SSDs are roughly in the $800-$1200 range. 4TB HDDs by comparison are quite cheap, as low as $89 for a certain Seagate model (I used the Western Digital Reds which for 4TB at the moment are a little higher, $115... for the 6TB model it is $178).

While I definitely wouldn't say "HDDs will always be around", the price difference is very high right now to justify the superior properties of SSD. Backblaze seems to be in agreement here (https://www.backblaze.com/blog/ssd-vs-hdd-future-of-storage/). I guess the question is how long it will take for large capacity SSDs to scale down in price for them to be competitive. Until that happens, I imagine HDDs have a decent future left, if not on consumer devices then at least as drives for cloud / data center storage.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#112

Post by londons_explore »

wtallis wrote: post #82
StillBored wrote: post #58

Earlier quoted context omitted.

You might be right, but keep in mind that flash has been scaling due to the shrinking semiconductor feature sizes (and additional layers/etc). So a large part of flash's core R&D & production costs are being spread over all the logic being produced. That has been hitting a wall, so while the capacity/price curves for flash look nice, they likely won't continue, which leaves open the possibility that if rust actually…

Horizontal feature sizes for flash memory stopped shrinking years ago. The continued improvements in density and production cost have been the result of R&D that is very specifically focused on 3D NAND flash memory and has little in common with R&D for logic circuit fabrication. That said, on the horizon of multiple years, I agree that the future scalability of NAND flash doesn't look quite as promising as HAMR/MAMR…

Multi-actuator tech sounds interesting, and I wouldn't be surprised to see drives with 5, 10, 50 or 100 read heads per platter at some point.

With 100 read heads per platter, typical seek time is cut by a factor of 100. That won't let them overtake SSD's, but at least allow them to close the gap.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#113

Post by ksec »

londons_explore wrote: post #46
tallanvor wrote: post #26

Earlier quoted context omitted.

HAMR and then HDMR are expected to allow data densities to increase by 5 to 10 times what is currently achievable. HAMR will probably start showing up in a year or two. Spinning drives are definitely not going away anytime soon unless there is a much more significant drop in the cost of SSDs.

Investment in new spinning drive technologies is going away though. Nobody wants to spend R&D money on coming up with patents and ideas which will be worthless in 5 years when SSD's overtake. Science investment requires a new technology to have a prospect of a return for most of the ~20 year patent lifespan for it to look like a good investment, and spinning bits of metal aren't that right now.

Not in the next 10 years. Further than that I don't know. SSD won't be cheaper than HDD per GB in 5 years time, the cost of building Flash and scaling down Flash, Multi Layer Flash, 2.5D / 3D/ 4D Flash ( What ever the manufacture wants to call them ) are also going up. Return of investment is taking longer ( Even with the previous high NAND price ). Moore's Law is dead, and it is not only just CPU.

Theoretically speaking there should be a point where the TCO of NAND Flash would cross HDD. But as NAND scales down, it also reduces its write cycle.

I was never a believer in HAMR, the technologies parent mentioned which Seagate announced in 2012, the idea just seems too unrealistic. The approach WD taking MAMR is much better using Magnetic Field. BPM is also far off, but BPM has been in research for nearly a decade, and MAMR should be here in 2019. All of these R&D will come to fruition in the next few years, where we expect HDD to scale to 100TB in the next 10 years.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#115

Post by wtallis »

londons_explore wrote: post #112
wtallis wrote: post #82

Earlier quoted context omitted.

Horizontal feature sizes for flash memory stopped shrinking years ago. The continued improvements in density and production cost have been the result of R&D that is very specifically focused on 3D NAND flash memory and has little in common with R&D for logic circuit fabrication. That said, on the horizon of multiple years, I agree that the future scalability of NAND flash doesn't look quite as promising as HAMR/MAMR…

Multi-actuator tech sounds interesting, and I wouldn't be surprised to see drives with 5, 10, 50 or 100 read heads per platter at some point. With 100 read heads per platter, typical seek time is cut by a factor of 100. That won't let them overtake SSD's, but at least allow them to close the gap.

So far, nobody has announced plans to manufacture hard drives with two read heads per platter, so speculating about 100 heads per platter seems rather unrealistic. The multi-actuator technology that is actually being developed by Seagate still has only one read head per platter, but out of the eight or so platters in a drive, the read heads for four of them will be controlled by one actuator and the read heads for the other four platters will be controlled by the second actuator.

Going all the way to 100 read heads per platter would be insanely expensive and would massively increase drive failure rates, while still leaving them about four times slower for random reads than the slowest $35 SSD on the market. This will never turn into a viable product.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#116

Post by rini17 »

quasarj wrote: post #97

So does anyone know of a way to take a set of files and write them to an HDD, in NTFS or exFAT format, in a single sequential write? Essentially building the FS on-the-fly (because we're talking about datsets that are much too large to fit into memory)?

ROMFS (there are several variants in linux kernel) are for this use case,but these are only read-only.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#117

Post by wtallis »

apiudit wrote: post #19
gsich wrote: post #11

Earlier quoted context omitted.

>We are clearly close to the end of spinning rust In every aspect, except price. Samsung 1 TB SSD for 150€, Seagate 8 TB for 220€.

1tb Samsung 860 Evo is more than 850€ in my country...

No, it isn't. That's about 6x the price in the US and at least 5x the price in Australia. No combination of VAT and shipping fees can account for that big of a discrepancy. You're probably just looking at a retailer that has inflated the price while they're out of stock. Try getting a quote from someone who has stock in your country ready to ship.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#118

Post by imtringued »

throwaway2048 wrote: post #30
chrisper wrote: post #23

Earlier quoted context omitted.

Raid 01 has its own risk. If the wrong two disks fail your entire array is toast

as opposed to raid 5 where if any two disks fail your array is toast, raid 6 increases this to 3. However both raid 5 and 6 have 2 huge problems: Data inflight at write time (power/hardware failures are more likely to corrupt the array, especially silently, which is the worst outcome). Parity calculations require you to spin up the whole raid5/6 array during a rebuild, massively increasing the chance of a multi drive…

>through what is essentially an all day full tilt stress test is a terrible, terrible idea

The rebuild isn't putting the disks under stress. The sister drive has already failed silently but you only notice this once you start the rebuild. The solution is to check the disks once a week by fully reading every sector.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#119

Post by zaarn »

nine_k wrote: post #25
chrisper wrote: post #23

Earlier quoted context omitted.

Raid 01 has its own risk. If the wrong two disks fail your entire array is toast

You can upgrade a 2-disk RAID1 to a 3-disk RAID5, then chain them to RAID0 as normal. It gives you a better chance to keep data intact, hopefully without lowering the write speed seriously. https://en.wikipedia.org/wiki/Nested_RAID_levels#RAID_50_(RA...

RAID 50 doesn't really solve it, it exposes you to some more risk since you can still die with 2 disks but now you have more disks in each sub array.

The correct answer is either a 3-mirror RAID1 or RAID6.

Bcachefs also promises some solution to this by allowing both erasure encoding and replication to co-exist, according to it's documentation.

Re: 15TB HDDs: Western Digital Unveils the Ultrastar DC HC620

#120

Post by e12e »

Hei1Fuya wrote: post #13
chrisper wrote: post #2

It's an SMR drive. So better for archiving than regular IO

Copy on write filesystems can probably be optimized for SMR by using TRIM commands to punch holes and rewrite the content sequentially in a new zone. Afaik both zfs and btrfs have plans to do this. That way they can be useful for more than archival.

Still seems random access might be an issue. But would love to see how eg nilfs2 (maybe on top of software raid) benchmarks against zfs on these big drives.
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