What to do when pg_xlog directory has filled up the filesystem

Hi all,

Just curious about this issue as it has occurred on my 9.4.0 sandbox primary server. The link to the directory
specifiedin archive_command had disappeared, so the command  
specified in archive_command kept failing overnight. This resulted in many WAL segments piling up in the pg_xlog
directoryand a bunch of <wal name>.ready files appearing in the  
pg_xlog/archive.status directory. The filesystem had reached 100% full so the database quit and would not restart. I've
thoughtabout just moving some of the WAL segments  
temporarily to another filesystem, but which ones, oldest or newest? And is that really the best way to deal with this
orwhat is the best way to deal with this kind of issue? 
--
Jay