OpenSRF services spawn subprocesses called "drones" that do the actual work of the application. In some hardware setups it may be desirable to separate drone processes from the Apache processes by configuring OpenSRF processes to run on one or more "drone" or "application" servers. In the legacy PINES setup, this was done with the following steps:

1. exporting the /openils directory to the drone machines using NFS
2. NFS-mounting the head's /openils directory on each drone
3. setting up passwordless SSH keys between the head and the drones
4. configuring /home/opensrf/.oils_brick.cfg so that the brick_ctl.sh script can start and stop services on all machines within the brick
5. modifying the <hosts> section of opensrf.xml so that openils.settings runs on the head and all of the other services run on the drone server

In PINES' current implementation, we use single-server bricks.