6.2. I/O Scheduling with Red Hat Enterprise Linux as a Virtualization Host

When using Red Hat Enterprise Linux as a host for virtualized guests, the default cfq scheduler is usually ideal. This scheduler performs well on nearly all workloads.
However, if minimizing I/O latency is more important than maximizing I/O throughput on the guest workloads, it may be beneficial to use the deadline scheduler. The deadline scheduler is also the scheduler used by the tuned profile virtual-host.