Flashcache at Facebook: From 2010 to 2013 and beyond

This post details the evolution and optimization of Flashcache, a software-based caching solution implemented as a Linux kernel device mapper target. It describes its initial adoption in 2010 to address storage cost and performance trade-offs, and subsequent performance analysis and improvements made between 2010 and 2013. Key contributions include enhancing read-write distribution through changes in associativity and hashing, optimizing cache eviction by adopting LRU with mid-point insertion, and improving write efficiency with a unified dirty data eviction method. These optimizations led to significant reductions in disk I/O operations, improving the performance and efficiency of Facebook's storage infrastructure.