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Comment by searchfaster | Hacker News Reader

Yes, but this is just 16GB or 32GB, which is not really big.

Think of it as a write-back cache to sliw HDDs. You will be able to have very fast consistent DURABLE cache writes which will be written back async to slow HDDs. 32GB is more than enough for this case.

Or your filesystem caching often requested disk blocks which had to be removed because of memory pressure.

Sure, but why this instead of a 32GB SLC SSD?

Because this is supposed to faster and have much longer operational life than a NAND-flash based SSD used for the same purpose.

Back when Intel first announced their crosspoint memory they predicted that it would have a much longer operational life than traditional SSDs. Now that they've finally managed to create a working product with it they're only saying that it has a lifetime a few times longer than SLC NAND.

Since write endurance is spread over the whole SSD you can easily get a cache four as big as the Optane equivalent for I presume the same amount of money and end up with the same endurance, higher throughput, slightly more latency, and a much higher cache hit rate.

That's actually great, because most drives these days are the much lower endurance MLC, rather than SLC. So we get much higher density AND higher endurance, for less money (assuming SLC is still pricey, I haven't looked recently).

Are 32GB SLC SSDs even available any more?

They are, from companies like Transcend. But they're targeted for industrial applications and use relatively low performance SATA controllers.

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