Was the entire pancake analogy a setup for the 'have your pancakes and eat them too' joke?
Optane Memory – A bridge between DRAM and storage
21–30 of 109 posts
Re: Optane Memory – A bridge between DRAM and storage
#22It looks to be an accelerator cache for HDDs, but slower than an SSD, with fairly low capacity. And it requires a 7th gen intel processor, so this isn't a performance boost for older PCs either. Exactly who is this aimed at?
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.
Re: Optane Memory – A bridge between DRAM and storage
#23It looks to be an accelerator cache for HDDs, but slower than an SSD, with fairly low capacity. And it requires a 7th gen intel processor, so this isn't a performance boost for older PCs either. Exactly who is this aimed at?
Nobody.
You lose SSD transfer speed, while gain _some_ hardware response latency.
NVMe response latency (on hardware side, not OS) is around 14-15micro-seconds on reads, and tops out at 200micro-seconds on writes [1]. Which is nearly 2-3 orders of magnitude below spinning rust. While Optane can halve this to 7micro-seconds on reads. The price/pref vs established NVMe tech is non-existent.
When I can spend $X/GB to get a 2000% performance bump, its hard to justify spending $X*4/GB to get 2050% performance bump. Most applications/data centers have yet to transfer to NVMe. Offering marginal gains a sizable markup is a risky strategy.
Furthermore Optane is nearly 2 orders of magnitude lower than RAM in latency, and 5 orders of magnitude lower transfer. So the idea of "non-volatile RAM" has yet to arrive.
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Also "Transparent to the OS" should strike fear in your heart. The OS's job is to manage hardware, memory, and caches. Why drop this?
Re: Optane Memory – A bridge between DRAM and storage
#24It looks to be an accelerator cache for HDDs, but slower than an SSD, with fairly low capacity. And it requires a 7th gen intel processor, so this isn't a performance boost for older PCs either. Exactly who is this aimed at?
Looks faster than an SSD to me. From the FAQ: "Q4: Will Intel Optane memory also accelerate an SSD? If so how much? A: Yes. Intel Optane memory can be used to accelerate any type of SATA-based storage media, including SATA SSDs, However, the performance benefit of adding Intel Optane memory will be greater on slower storage devices like an HDD versus a relatively faster storage device like a SATA-SSD. Additional perf…
I don't think GP is talking about SATA SSD. Based on the performance, definitely it is PCIe NVMe SSD ( 960 IMO )
Re: Optane Memory – A bridge between DRAM and storage
#25The only thing could get from Optane is QD1 performance. It is impressive (5x faster than current gen NVMe SSD). But everything else is just soso compared to NVMe SSD.
Re: Optane Memory – A bridge between DRAM and storage
#26I wonder if there is a use-case for this to be the storage device in a low-end VPS?
Re: Optane Memory – A bridge between DRAM and storage
#27I thought I could throw away my DRAM and SSD, but it looks like for now it's just another cache level.
They're a long way from realizing the full potential of the technology. Right now they're hugely limited by the interconnect. Also, if they reach some of the goals they've been talking about, it might need differently-designed operating systems to really work.
I mean, Single-Level-Storage is hardly a new concept - I don't think we need entirely new operating systems to gain benefits, but for more applications and enabling technologies to be designed around it.
LMDB, for example, would be a great fit with Optane already. Really, anything that uses mmap() is.
Re: Optane Memory – A bridge between DRAM and storage
#28Quite a bit of marketing-speak here on the official site, without a lot of technical details. I know the Optane SSD drives are fast -- is this just device-side driver software that allows you to virtually expand available "RAM" and mmap it to the SSD? Why just i7 CPUs? Is there a hardware component? "Just download and install the driver..." (Linux?)
Seems like its some i3/i5/i7, only recent ones? Must be some hardware component to it that makes the SSD look like memory to the system, perhaps as another NUMA zone (could you have a huge NUMA zone with no CPU attached?)
Maybe the CLWB instruction?
Re: Optane Memory – A bridge between DRAM and storage
#29[deleted]
Re: Optane Memory – A bridge between DRAM and storage
#30It looks to be an accelerator cache for HDDs, but slower than an SSD, with fairly low capacity. And it requires a 7th gen intel processor, so this isn't a performance boost for older PCs either. Exactly who is this aimed at?
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 think in the medium to longer term M.2/NVMe will be much faster.