> I think it's in-memory. In-memory support was added later, though I'm not sure if it made it into a release as I stopped paying attention around when they st

> I think it's in-memory. In-memory support was added later, though I'm not sure if it made it into a release as I stopped paying attention around when they started developing that feature. They originally ran exclusively on specialized appliances having battery-backed write caches. The implementation is all in C using Linux AIO w/epoll. It's a sophisticated, high-performance storage engine. When everyone shifted to the cloud and stopped owning hardware, Clustrix was forced to add a file-based backend. This still uses the high-performance AIO+epoll engine.