# File common/lib/symbiosis/host.rb, line 209
    def self.primary_backup_space(backup_space_filename=BACKUP_SPACE_FILENAME)
      if File.exists?(backup_space_filename)
        File.open(backup_space_filename){|fh| fh.readlines}.first.to_s.chomp
      else
        self.backup_spaces.first
      end
    end