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

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