public static BackupStatus backupAllMembers(DistributionManager dm, File targetDir,
      File baselineDir) throws AdminException {
    String baselineDirectory = baselineDir == null ? null : baselineDir.toString();
    return new BackupOperation(dm, dm.getCache()).backupAllMembers(targetDir.toString(),
        baselineDirectory);
  }
Shutdown all members.

@param timeout the amount of time (in ms) to spending trying to shutdown the members
       gracefully. After this time period, the members will be forceable shut down. If the
       timeout is exceeded, persistent recovery after the shutdown may need to do a GII. -1
       indicates that the shutdown should wait forever.
geode-core/src/main/java/org/apache/geode/admin/internal/AdminDistributedSystemImpl.java