pfs —
save and restore information for NAT and state tables
The pfs command allows state information created for NAT
  entries and rules using “keep state” to be locked (modification
  prevented) and then saved to disk, allowing for the system to experience a
  reboot, followed by the restoration of that information, resulting in
  connections not being interrupted.
  - -b
- The information are read or stored using binary format. The default format
      is a readable ASCII format, similar to pfctl.conf
      syntax.
- -l
- Lock state tables in the kernel.
- -Rfilename
- Restore information from filename and load it into
      the kernel. The state tables are locked at the beginning of this operation
      and unlocked once complete.
- -rfilename
- Read information in from filename and load it into
      the kernel. This requires the state tables to have already been locked and
      does not change the lock once complete.
- -u
- Unlock state tables in the kernel.
- -v
- Provide a verbose description of what's being done.
- -Wfilename
- Write information from the kernel out to filename.
      The state tables are locked at the beginning of this operation and
      unlocked once complete.
- -wfilename
- Write information from the kernel out to filename.
      This requires the state tables to have already been locked and does not
      change the lock once complete.