Large scale caching systems are making a transition from DRAM to SSDs for cost/power trade-offs and that brings out interesting challenges to both software and hardware. At Facebook, CacheLib is a widely deployed general purpose caching engine, enabling this transition through hybrid caching. In this talk, we introduce hybrid cache, highlight the challenges of hybrid caches at scale and the various techniques Facebook adopts to tackle these challenges. Looking forward CacheLib offers a platform for the software, hardware and academic community to collaborate on solving the upcoming challenges with new hardware and software solutions for caching. This talk is expected to take 30 minutes.