Creating a Swapfile on FreeBSD

  1. The GENERIC kernel already includes the memory disk driver (md(4)) required for this operation. When building a custom kernel, make sure to include the following line in your custom configuration file:
    device   md
    For information on building your own kernel, please refer to Chapter 9.
  2. Create a swapfile (/usr/swap0):
    # dd if=/dev/zero of=/usr/swap0 bs=1024k count=64
  3. Set proper permissions on (/usr/swap0):
    # chmod 0600 /usr/swap0
  4. Enable the swap file in /etc/rc.conf:
    swapfile="/usr/swap0"   # Set to name of swapfile if aux swapfile desired.
  5. Reboot the machine or to enable the swap file immediately, type:
    # mdconfig -a -t vnode -f /usr/swap0 -u 0 && swapon /dev/md0