code: public boolean setReplication(String src, short replication)
      throws IOException {
      boolean status = setReplicationInternal(src, replication);
      getEditLog().logSync(false);
      if (status && auditLog.isInfoEnabled()) {
        logAuditEvent(getCurrentUGI(),
          Server.getRemoteIp(),
          "setReplication", src, null, null);
      }
      return status;
    }
docs: Set replication for an existing file.
  <p/>
  The NameNode sets new replication and schedules either replication of
  under-replicated data blocks or removal of the eccessive block copies
  if the blocks are over-replicated.
  
  @param src         file name
  @param replication new replication
  @return true if successful;
  false if file does not exist or is a directory
  @see ClientProtocol#setReplication(String, short)