Kangaroo: A new flash cache optimized for tiny objects

[el_duderino]

https://engineering.fb.com/2021/10/26/core-data/kangaroo/

[rektide]

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.

[cowsandmilk → rektide]

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.

[pritambaral → rektide]

KV stores aren't allowed to drop arbitrary keys.

[thecleaner]

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 ?

[almog → thecleaner]

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