Kangaroo: A new flash cache optimized for tiny objects

engineering.fb.com

30 pointsel_duderino5 comments

If Kangaroo as they say is not a k-v store, as this says, how does one talk-about/describe which cache items they wish to retrieve or update? Don't we need a name/key to talk about the value being cached, so we know what to ask for next time?

I have it earmarked to go read this paper more closely, but the claim that this is not a k/v store made me confused.

Their point is that they are not a store, you are focusing on the key-value aspect. In a store, if I write, the expectation is that the write will occur. They gain efficiency by sometimes deciding the write is not worth the cost and evicting rather than writing.

KV stores aren't allowed to drop arbitrary keys.

Any references on what's a log structured cache ?

Also I don't understand this claim in the paper - "At a high level, KSet minimizes DRAM usage and KLog minimizes flash writes." Why ?

I'm assuming they use that term to say LSM Tree (log-structured merge-tree).

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