Kangaroo: A new flash cache optimized for tiny objects

Introduced Kangaroo, a novel flash cache design optimized for tiny objects (~100 bytes or less). Kangaroo combines log-structured (KLog) and set-associative (KSet) cache components to reduce both DRAM overhead and write amplification. It employs a threshold admission policy to amortize writes to KSet over multiple objects and a new eviction policy to minimize cache misses. Evaluated using production social graph caching workloads from Facebook and Twitter, demonstrating a 29% reduction in misses under realistic constraints compared to prior designs.