The Unwritten Contract of Solid State Drives.

We perform a detailed vertical analysis of application performance atop a range of modern file systems and SSD FTLs. We formalize the \"unwritten contract\" that clients of SSDs should follow to obtain high performance, and conduct our analysis to uncover application and file system designs that violate the contract. Our analysis, which utilizes a highly detailed SSD simulation underneath traces taken from real workloads and file systems, provides insight into how to better construct applications, file systems, and FTLs to realize robust and sustainable performance.