> With I/O being the top bottleneck in modern databases and web applications, a lot of what people call "unpredictable performance" or "virtualization overhead"

> With I/O being the top bottleneck in modern databases and web applications, a lot of what people call "unpredictable performance" or "virtualization overhead" has mostly to do with sharing (and thin provisioning) storage devices between multiple servers/nodes. The thing is, most of the problem with sharing a disk simply goes away once you go SSD. Spinning disk has the characteristic that sequential access is pretty good... and random access is terrible. If you have two processes both streaming sequentially off the same disk at the same time, if your scheduling algorithm doesn't allow for terrible latency, the disk is going to see random access. This is why spinning disk is so terrible for multi-user setups. SSD doesn't have that problem. SSD has problems with writes that are not cell-aligned, but this is functionally similar to the problems raid5 has, and much like raid5, it's not a problem when it comes to reads.