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Optane Memory – A bridge between DRAM and storage

intel.com

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Re: Optane Memory – A bridge between DRAM and storage

#91

Post by fulafel »

Joeri wrote: post #54
slizard wrote: post #33

Earlier quoted context omitted.

Partly it is just marketing fluff, Intel trying to save their face and hoping that most will not remember the promises of revolutionary product while what they released is barely evolutionary. Can't find a better article right now than this SEmiaccurate rant [1] which is quite inflammatory, but does not push falsehoods AFAICT. But Intel has essentially walked back from the 100-1000x improvements it initially claimed…

You have to remember thus is a first gen product. Early ssd's were abysmal.

The first SSDs were DRAM based and pretty fast for the time, see eg. https://en.wikipedia.org/wiki/Cray_Y-MP. (SRAM, now used in CPU caches, was used for the whole main memory on that machine)

Re: Optane Memory – A bridge between DRAM and storage

#92

Post by hoschicz »

dsr_ wrote: post #71
faragon wrote: post #49

How it compares to massive swapping to typical SSD?

Badly. Suppose you have a 16GB laptop and the 16GB optane. When you close your laptop to take it to a mid-morning meeting, you've just done a whole drive write. Do it again at lunch, twice in the afternoon and again when you get home, you're at 5 of your 6 drive writes. Now imagine you open your laptop 8 or 12 times a day...

Closing laptop usually mean suspend to memory, not disk.

Re: Optane Memory – A bridge between DRAM and storage

#93

Post by Dylan16807 »

angry_octet wrote: post #80
convolvatron wrote: post #47

Earlier quoted context omitted.

seems like it might be useful as a transaction log?

The latency of a regular SATA SSD is more than good enough if you want a log of writes to spinning rust. The increased write endurance might be appealing for something like a ZFS intents log (ZIL). Too small to provide much of an cache, when you can have 256GB of SSD for the same price. It is a pity that the marketing docs don't address how this impacts on write consistency. Instant write sync is the primary advantag…

> The increased write endurance might be appealing for something like a ZFS intents log (ZIL).

These first generation products don't actually have better endurance, though.

Re: Optane Memory – A bridge between DRAM and storage

#94

Post by Razengan »

dsr_ wrote: post #71
faragon wrote: post #49

How it compares to massive swapping to typical SSD?

Badly. Suppose you have a 16GB laptop and the 16GB optane. When you close your laptop to take it to a mid-morning meeting, you've just done a whole drive write. Do it again at lunch, twice in the afternoon and again when you get home, you're at 5 of your 6 drive writes. Now imagine you open your laptop 8 or 12 times a day...

> When you close your laptop ... you've just done a whole drive write.

Which OS does that? I know macOS doesn't, but it still manages to recover documents in the event of a crash thanks to NSDocument autosaving anyway.

Re: Optane Memory – A bridge between DRAM and storage

#95

Post by bobbington »

lallysingh wrote: post #67
searchfaster wrote: post #61

Earlier quoted context omitted.

Thanks ! Finally a place to lookup pricing information. Also if you are already mmap'ing some big file which needs frequent access, I do not see how this will help ?

This. A RAM based cache sounds substantially more performant. I think this may be for clients that can't do much more than swap hardware to make their setup faster. Either it's a lack of control over their OS setup, or a desire to fine-tune caching for a specific device, or a lack of ability to change existing settings.

Ram cache won't improve boot times

Re: Optane Memory – A bridge between DRAM and storage

#96

Post by sliken »

2bluesc wrote: post #20
2bluesc wrote: post #16

Anandtech, as usual, has a good article: http://www.anandtech.com/show/11227/intel-launches-optane-me... > The Optane Memory products are squeezing into a relatively small niche for limited budgets that require a lot of storage and want the benefit of solid state performance without paying the full price of a boot SSD. Intel notes that Optane Memory caching can be used in front of hybrid drives and SATA SSDs, but the…

Interesting comment from Anandtech [0] > Keep in mind that consumer NVMe SSDs that boast throughput of 2GB/s or more generally do not reach their peak at low queue depth. Optane is supposed to be able to drive 1200MB/s read throughput at low queue depth (not sure why they listed QD4), so there is potential for some performance improvement here. Most consumer workloads never get out of low queue depth territory, so th…

Dunno, I find 1.2-1.6GB/sec on my samsung s950 all the time. The benchmarks I've seen do not show any noticeable difference between SATA and NVMe. Sure geeks like the idea of a lower head protocol, but truth is the protocol is not the bottlneck.

Seems like Optane is a solution looking for a problem to fix. Normal M2 SATA's do fine: # dd if=/dev/sdb of=/dev/null bs=131072 1953586+1 records in 1953586+1 records out 256060514304 bytes (256 GB, 238 GiB) copied, 159.18 s, 1.6 GB/s

(cold cache on a machine with 16GB ram).

Re: Optane Memory – A bridge between DRAM and storage

#97

Post by sliken »

dragontamer wrote: post #58
nilanjonB wrote: post #43

Earlier quoted context omitted.

I'm wondering what market their actually aiming for? non-NVMe drive users? If the gains aren't that significant, why would people buy it and why would PC maker want to use it?

Its pretty crap for the consumer market. Your typical MLC SSD (or even TLC SSD) over SATA is more than sufficient for the consumer market, at prices that actually will be used (although even a TLC SSD seems to be considered "high end" by my family members...) --------- The Optane memory seems to have a niche in replacing DRAM servers. So instead of running Redis, MySQL, or Postgres on DRAM, you can run it on Optane i…

Er, what? Optane has half the latency of DDR4? Source?

Re: Optane Memory – A bridge between DRAM and storage

#98

Post by sliken »

dv_dt wrote: post #30
1001101 wrote: post #22

Earlier quoted context omitted.

My interpretation is that it is a fancy cache using a new type of memory, XPoint, a non-volatile phase change memory, with greater endurance (and cost) than NAND sitting on the M.2 bus, combined with OS drivers to assist with the mapping. The idea is M.2 speed > SATA, but the dynamic M.2 caching isn't native to the OS, so drivers are required to intermediate. Pretty underwhelming relative to the hype.

M.2 is a hardware connector. It can carry various flavors of SATA or NVMe over PCIe lanes. Generally M.2 drives will be at least equal to a SATA drive on a traditional SATA connector, with the potential to be much faster. However, even some of the m.2/NVMe drives which are much faster at the bus level seem to be bottlenecked by some design assumptions (both inside the drive and above in the various OS layers). I thin…

Just buy a nicer M2 and you get plenty of performance without special drivers: # dd if=/dev/sdb of=/dev/null bs=131072 1953586+1 records in 1953586+1 records out 256060514304 bytes (256 GB, 238 GiB) copied, 159.18 s, 1.6 GB/s

Re: Optane Memory – A bridge between DRAM and storage

#99

Post by markvdb »

wtallis wrote: post #85
mtgx wrote: post #68

Earlier quoted context omitted.

> Intel's claim has been in the past that its density can exceed SSDs by a healthy margin Seems doubtful they would reach that goal until SSDs hit some kind of hard plateau (kind of like HDDs did). Toshiba plans to make a 100TB SSD over the next couple of years, and I believe Samsung has already announced a 16TB SSD. I doubt 3D Xpoint can catch-up with those in the given time frame.

NAND flash memory already hit the wall for horizontal shrinks, and some products plowed past that limit and into the regime where day to day use was invoking the second level error correction methods to compensate for data degradation. 3D NAND turned the clock back on horizontal scaling and cell sizes by several years, and now the only scaling opportunity is to increase layer count. That's not going so well. Samsung…

I can see some potential in things like RERAM to scale beyond 3D NAND and bridge the SSD/RAM gap. I like the technological elegance of non-filamentary RERAM [2] in particular.

[1] https://en.wikipedia.org/wiki/Resistive_random-access_memory [2] http://www.4dsmemory.com

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