Installation guide

Using the para-virtualized drivers with Red Hat Enterprise Linux 3.9 guests

modprobe virtio_pci

Reboot the guest to load the kernel modules.

Adding the para-virtualized drivers to the initrd RAM disk

This procedure covers loading the para-virtualized driver modules with the kernel on a Red Hat

Enterprise Linux 3.9 or newer guest by including the modules in the initrd RAM disk. The mkinitrd tool

configures the initrd RAM disk to load the the modules. Specify the additional modules with the --

with parameter for the mkinitrd command. Append following set of parameters, in the exact order,

when using the mkinitrd command to create a custom initrd RAM disk:

--with virtio --with virtio_ring --with virtio_blk --with virtio_net --with virtio_pci

AMD64 and Intel 64 issues

Use the x86_64 version of the virtio package for AMD64 systems.

Use the ia32e version of the virtio package for Intel 64 systems. Using the x86_64 version of the

virtio may cause a 'Unresolved symbol' error during the boot sequence on Intel 64 systems.

Network performance issues

If you experience low performance with the para-virtualized network drivers, verify the setting for the

GSO and TSO features on the host system. The para-virtualized network drivers require that the GSO

and TSO options are disabled for optimal performance.

Verify the status of the GSO and TSO settings, use the command on the host (replacing interface

with the network interface used by the guest):

# ethtool -k interface

Disable the GSO and TSO options with the following commands on the host:

# ethtool -K interface gso off

# ethtool -K interface tso off

Para-virtualized driver swap partition issue

After activating the para-virtualized block device driver the swap partition may not be available. This

issue is may be caused by a change in disk device name. To fix this issue, open the /etc/fstab file

and locate the lines containing swap partitions, for example:

/dev/hda3 swap swap defaults 0 0

The para-virtualized drivers use the /dev/vd* naming convention, not the /dev/hd* naming

convention. To resolve this issue modify the incorrect swap entries in the /etc/fstab file to use the

/dev/vd* convention, for the example above:

/dev/vda3 swap swap defaults 0 0

Save the changes and reboot the virtualized guest. The guest should now correctly have swap

partitions.