Lessons Learned from 6 Years of IO Scheduling at ScyllaDB

Pavel (Xemul) Emelyanov Pavel is a principal engineer at ScyllaDB. He is an ex-Linux kernel hacker now speeding up row cache, tweaking the IO scheduler and helping to pay back technical debt for component interdependencies. Scheduling requests of any kind always serves one purpose: gain control over the priorities of those requests. In the priority-less system, there’s no need to schedule; just putting whatever arrives into the queue and waiting until it finishes is enough. I’m a principal engineer for