> Would you be able to give more details as to how you use disks as raw block devices, bypassing the filesystem? For example, the kind of abstraction layers you use, their interfaces and methods, disk layout of extents, metadata layout, consistency issues, fsync issues, and the various performance advantages from bypassing the filesystem?

Yeah, we're going to write a whole blog post on this sort of stuff sometime soon. Needless to say, it's a big topic!