The following tasks and tips can assist you with increasing the performance of your Red Hat Enterprise Linux host. Additional tips can be found in the Red Hat Enterprise Linux Virtualization Tuning and Optimization Guide
Run SELinux in enforcing mode. Set SELinux to run in enforcing mode with the setenforce command.
# setenforce 1
Remove or disable any unnecessary services such as AutoFS, NFS, FTP, HTTP, NIS, telnetd, sendmail and so on.
Only add the minimum number of user accounts needed for platform management on the server and remove unnecessary user accounts.
Avoid running any unessential applications on your host. Running applications on the host may impact virtual machine performance and can affect server stability. Any application which may crash the server will also cause all virtual machines on the server to go down.
Use a central location for virtual machine installations and images. Virtual machine images should be stored under /var/lib/libvirt/images/. If you are using a different directory for your virtual machine images make sure you add the directory to your SELinux policy and relabel it before starting the installation. Use of shareable, network storage in a central location is highly recommended.