On Tue, Jan 17, 2017 at 12:50:43PM -0500, Josh Boyer wrote:
Well, I'm starting from Michael's premise that deadline would be better for latency for most desktop users (regardless of disk type), and clearly better when using SSD. This leads me to a different conclusion than the above.
Then set it as such in Workstation. I don't see how your conclusion conflicts with mine at all.
Well, if it seems like the best default for Workstation (and therefore probably also most of the desktop Spins) *and* for server, doesn't changing the overall default make the most sense?
It's irrelevant for cloud and any other virt deployment of Atomic or Server. As far as I know, the special case on hardware where cfq is better is the one I outlined (on hardware, single spindle, prefer throughput, mixed workload) and I agree that it's okay to expect sysadmins to handle that.
Why is it irrelevant on virt? Do people not care about local storage impacts of their guests? That would be surprising.
It's relevant to virt hosts, but not to cloud and virt _guests_, where the io scheduler is bypassed completely. See http://www.linux-kvm.org/images/6/63/02x06a-VirtioBlk.pdf