[libvirt-users] VM Performance using KVM Vs. VMware ESXi

[Dominique Ramaekers]

In your network interface, it’s not discribed which interface to use. So it will use system standard. If I’m not wrong, RHEL uses virtio then… Maybe, it’s still a good idea to put ‘<model type='virtio'/>’ inside the <interface ‘bridge’> section.

Daniel beat me to it about the ide-disk (about not using that)… Also don’t use qcow2 for disk-format if you don’t need to. I prefer raw. Qcow2 has a lot of good points but speed isn’t one of them.

For everything you can, use virtio. This driver make sure the io-activities goes directly between guest kernel and host kernel without noticeable delay…


Van: Jatin Davey [mailto:jashokda at cisco.com]
Verzonden: dinsdag 14 april 2015 13:24
Aan: Dominique Ramaekers; libvirt-users at redhat.com<mailto:libvirt-users at redhat.com>
Onderwerp: Re: [libvirt-users] VM Performance using KVM Vs. VMware ESXi

On 4/14/2015 4:42 PM, Dominique Ramaekers wrote:
About Spice: I think it’s good practice to use spice because it improves the performance of the VM in general by improving screen performance. If your VM is constantly displaying output, you’ll probably will notice a difference.
[Jatin] Ok, This is not my concern as of now. I will take a look at it sometime later.

About virtio: You can see it in the settings. Better yet, it’s in your XML. If you post your XML, we can take a look…

Here is the xml associated with my VM:

********************************
<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit ********
or other application using the libvirt API.
-->

<domain type='kvm'>
  <name>******</name>
  <uuid>********</uuid>
  <title>*******</title>
  <description>***********</description>
  <metadata>
    <template name="****">
      <disks>
        <location type="local" name="Local" path="/VM_DATA_01"/>
        <disk>
          <source file="/opt/am-data/sw-download/apps//****/ovf/****/system.vmdk" format="vmdk"/>
          <target file="/VM_DATA_01/****/****.qcow2" format="qcow2"/>
        </disk>
      </disks>
      <applications>
        <application>
          <name>****</name>
          <description>****</description>
          <version>****</version>
          <icon>****</icon>
        </application>
      </applications>
    </template>
  </metadata>
  <memory unit='KiB'>20971520</memory>
  <currentMemory unit='KiB'>20971520</currentMemory>
  <vcpu placement='static'>8</vcpu>
  <os>
    <type arch='x86_64' machine='rhel6.5.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none'/>
      <source file='/var/lib/libvirt/images/****.qcow2'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <interface type='bridge'>
      <mac address='52:54:00:c9:58:c9'/>
      <source bridge='br332'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0' keymap='en-us' passwd='*****'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </memballoon>
  </devices>
</domain>
*******************************************

Thanks
Jatin
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