FreeBSD Guest Notes

Tweaks and tips for better performance with FreeBSD on KVM.

Note: This has only been tested with FreeBSD 9.0-RELEASE (and patch levels).

Create VM

• Download the FreeBSD 9.0-amd64 DVD ISO (from here) and transfer it to your VM server.
• Create a new VM:
  • CPU: dual-socket or dual-core
  • RAM: 2GB (minimum)
  • Network: Intel e1000 (bridged)
  • Create a 32GB primary disk (scsi, qcow2)
  • Add FreeBSD 9.0-amd64 DVD ISO as an optical drive (scsi).

Install FreeBSD

• Power on the VM.
• It should boot to the FreeBSD 9.0-amd64 DVD ISO.
• System Components: Add "src".
• Disks: Guided, use entire disk.
• Network: Use ipv4 only (unless you also use ipv6).
• Services: Add ntpd.
• This should leave you with FreeBSD 9 installed on the 32GB primary drive.
• Shut down the VM after installation.
• Remove the ISO from the VM's optical drive (set to empty).
• Verify the VM's boot order is set to the primary hard disk first.

First Boot

• Power on the VM and log in.
• Set the time:

ntpdate -s pool.ntp.org

• Update the system:

freebsd-update fetch
freebsd-update install

• Reboot

Enable Virtio

• Install virtio-kmod:

cd /usr/ports/emulators/virtio-kmod && make clean install

• When prompted on each required package, accept defaults and OK.
• Copy the virtio modules into /boot/kernel directory:

cp -Rp /usr/local/modules/* /boot/kernel/
kldxref /boot/kernel

• Add the following to /boot/loader.conf:

virtio_load="YES"
virtio_pci_load="YES"
virtio_blk_load="YES"
if_vtnet_load="YES"
virtio_balloon_load="YES"

• Enable virtio for disk by changing your /etc/fstab entries to use the vtbd prefix. Example:

# Device        Mountpoint      FStype  Options Dump    Pass#
/dev/vtbd0p2    /               ufs     rw      1       1
/dev/vtbd0p3    none            swap    sw      0       0

• Enable virtio for network by changing the ifconfig_em0="DHCP" line in /etc/rc.conf to:

ifconfig_vtnet0="DHCP"

• Shutdown the VM

shutdown -p now

• Change VM's network and disk hardware to use virtio.
• Power on the VM.
• Verify that virtio is loading:

kldstat

Id Refs Address            Size     Name
 1   12 0xffffffff80200000 11cdab0  kernel
 2    5 0xffffffff813ce000 4ca0     virtio.ko
 3    1 0xffffffff813d3000 5880     virtio_pci.ko
 4    1 0xffffffff813d9000 5010     virtio_blk.ko
 5    1 0xffffffff813df000 aeb0     if_vtnet.ko
 6    1 0xffffffff813ea000 3210     virtio_balloon.ko

External Links

• How to upgrade FreeBSD 8.2 to FreeBSD 9.0 with Virtio - contains useful information on setting up virtio on freebsd 9.
• FreshPorts virtio-kmod page.