code: public static byte[] synchronizeSlaveHostController(ModelNode operation, final PathAddress address, HostFileRepository fileRepository, ContentRepository contentRepository, boolean backup, byte[] oldHash) {
          ModelNode operationContentItem = operation.get(DeploymentAttributes.CONTENT_RESOURCE_ALL.getName()).get(0);
          byte[] newHash = operationContentItem.require(CONTENT_HASH.getName()).asBytes();
          if (needRemoteContent(fileRepository, contentRepository, backup, oldHash)) {  // backup DC needs to  pull the content
              fileRepository.getDeploymentFiles(ModelContentReference.fromModelAddress(address, newHash));
          }
          return newHash;
      }
docs: Synchronize the required files to a slave HC from the master DC if this is required.
  @param fileRepository the HostFileRepository of the HC.
  @param contentRepository the ContentRepository of the HC.
  @param backup inidcates if this is a DC backup HC.
  @param oldHash the hash of the deployment to be replaced.
  @return true if the content should be pulled by the slave HC - false otherwise.