I split this off from T137928: Deploy phabricator to phab2001.codfw.wmnet to unblock that task because it doesn't actually depend on this one being completed.
See T164810: Switch phabricator production to codfw for a high-level outline of the steps. We should document the process more formally (and someplace besides phabricator since it won't be available when phabricator is offline).
Phabricator isn't considered the highest priority of systems to be getting online in the event of a disaster, nonetheless, it should be possible to recover relatively quickly so that we can utilize phabricator when coordinating the recovery of other systems.
Wikitech page for Disaster Recovery plan: https://wikitech.wikimedia.org/wiki/Phabricator/Disaster_Recovery