What We Need to Unlearn about Persistent Storage

System software engineers have long been taught that disks are slow and sequential I/O is key to performance. With SSD drives I/O really got much faster but not simpler. In this brave new world of rocket-speed throughputs an engineer has to distinguish sustained workload from bursts, (still) take care about I/O buffer sizes, account for disks' internal parallelism and study mixed I/O characteristics in advance. In this talk , I share some key performance measurements of the modern hardware we're taking at ScyllaDB and our opinion about the implications for the database and system software design.