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

Update Ports

It is a good idea to keep your installed ports up to date. This section shows you how to do so.

IMPORTANT: It is recommended practice to understand how port updates will impact your system. Some port upgrades can change the way the program works and can break the function of your machine. It is wise to do a full backup of your VM before updating ports.

• Update ports tree using portsnap:

portsnap fetch update

• Install portmaster:

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.