On 02/02/2016 05:34 PM, Benjamin Smith wrote: > We've ruled out IOPs for the disks (~ 20%) How did you measure that? What filesystem are you using? What is the disk / array configuration? Which database? If you run "iostat -x 2" what does a representative summary look like? > and raw CPU load (top shows perhaps > 1/2 of cores busy, but the system slows to a crawl. Define "busy"?