Hmm, it shows "4-EBS RAID" getting around 2.6x speedup for 4k writes. They don't say what RAID configuration they are using, but it sounds odd. A 4k write has

Hmm, it shows "4-EBS RAID" getting around 2.6x speedup for 4k writes. They don't say what RAID configuration they are using, but it sounds odd. A 4k write has to be synced to all the disks unless they have a <=4k stripe size AND are using RAID-0 AND are using stripe-aligned IO ops. It's also possible they use 4k writes to cache that end up forming large dirty blocks which the OS then syncs as larger I/Os. But that would be measuring something else than the benchmark claims.