KVM Best Practice

Use a block device to avoid additional software layers.

Best practices:asynchronous I/O model for KVM guests
Although the KVM supports thread pools for handling asynchronous I/O operations,
can also take advantage of the Kernel asynchronous I/O (AIO) support Forlinux.
By specifying aio=native in the QEMU-KVM command.

Best Practice:x2apic support for Red Hat Enterprise Linux 6 guests.

Best PRACTICE:NFS Remote Storage

Best practice:device-backed and file-backed virtual storage

Best PRACTICE:I/O schedulers
Best practice:optimize Block I/O performance by using the Deadline I/oscheduler

Virtio and Vhost_net
Vhost_net moving part of the Virtio drive from the user state to the kernel

Device assignment and SR-Iov

6.3. Caching Cache=none
6.4. I/O Mode io=native
6.5.2. Multi-queue VIRTIO-SCSI

KVM Best Practice