Performance issues on RHEL 5.8 KVM guest running on RHEL 6.3 hypervisor when compared to the same VMware guest.

Solution Verified - Updated -


  • Two servers, one performing okay and the other one performing poorly.

  • sar -u (past 6 hours)

** okay: vmware_guest01:       user=1-3%, system=1-2%,  iowait=< 0.1%
** poor: kvm_guest01:          user=2-5%, system=1-5%,  iowait=<0.04%, 


  • Red Hat Enterprise Linux (RHEL) 5.8 KVM guest
  • RHEL 6.3 KVM hypervisor

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