Java 类org.apache.hadoop.hdfs.server.datanode.fsdataset.RoundRobinVolumeChoosingPolicy 实例源码

项目：hadoop 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.fsRunning = true;
  this.datanode = datanode;
  this.dataStorage = storage;
  this.conf = conf;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);
  Collection<StorageLocation> dataLocations = DataNode.getStorageLocations(conf);
  List<VolumeFailureInfo> volumeFailureInfos = getInitialVolumeFailureInfos(
      dataLocations, storage);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volumeFailureInfos.size();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  storageMap = new ConcurrentHashMap<String, DatanodeStorage>();
  volumeMap = new ReplicaMap(this);
  ramDiskReplicaTracker = RamDiskReplicaTracker.getInstance(conf, this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volumeFailureInfos, datanode.getBlockScanner(),
      blockChooserImpl);
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, this);
  asyncLazyPersistService = new RamDiskAsyncLazyPersistService(datanode);
  deletingBlock = new HashMap<String, Set<Long>>();

  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    addVolume(dataLocations, storage.getStorageDir(idx));
  }
  setupAsyncLazyPersistThreads();

  cacheManager = new FsDatasetCache(this);

  // Start the lazy writer once we have built the replica maps.
  lazyWriter = new Daemon(new LazyWriter(conf));
  lazyWriter.start();
  registerMBean(datanode.getDatanodeUuid());
  localFS = FileSystem.getLocal(conf);
  blockPinningEnabled = conf.getBoolean(
    DFSConfigKeys.DFS_DATANODE_BLOCK_PINNING_ENABLED,
    DFSConfigKeys.DFS_DATANODE_BLOCK_PINNING_ENABLED_DEFAULT);
}

项目：big-c 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.fsRunning = true;
  this.datanode = datanode;
  this.dataStorage = storage;
  this.conf = conf;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);
  Collection<StorageLocation> dataLocations = DataNode.getStorageLocations(conf);
  List<VolumeFailureInfo> volumeFailureInfos = getInitialVolumeFailureInfos(
      dataLocations, storage);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volumeFailureInfos.size();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  storageMap = new ConcurrentHashMap<String, DatanodeStorage>();
  volumeMap = new ReplicaMap(this);
  ramDiskReplicaTracker = RamDiskReplicaTracker.getInstance(conf, this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volumeFailureInfos, datanode.getBlockScanner(),
      blockChooserImpl);
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, this);
  asyncLazyPersistService = new RamDiskAsyncLazyPersistService(datanode);
  deletingBlock = new HashMap<String, Set<Long>>();

  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    addVolume(dataLocations, storage.getStorageDir(idx));
  }
  setupAsyncLazyPersistThreads();

  cacheManager = new FsDatasetCache(this);

  // Start the lazy writer once we have built the replica maps.
  lazyWriter = new Daemon(new LazyWriter(conf));
  lazyWriter.start();
  registerMBean(datanode.getDatanodeUuid());
  localFS = FileSystem.getLocal(conf);
  blockPinningEnabled = conf.getBoolean(
    DFSConfigKeys.DFS_DATANODE_BLOCK_PINNING_ENABLED,
    DFSConfigKeys.DFS_DATANODE_BLOCK_PINNING_ENABLED_DEFAULT);
}

项目：hadoop-2.6.0-cdh5.4.3 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.fsRunning = true;
  this.datanode = datanode;
  this.dataStorage = storage;
  this.conf = conf;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);
  Collection<StorageLocation> dataLocations = DataNode.getStorageLocations(conf);
  List<VolumeFailureInfo> volumeFailureInfos = getInitialVolumeFailureInfos(
      dataLocations, storage);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volumeFailureInfos.size();

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  storageMap = new ConcurrentHashMap<String, DatanodeStorage>();
  volumeMap = new ReplicaMap(this);
  ramDiskReplicaTracker = RamDiskReplicaTracker.getInstance(conf, this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volumeFailureInfos, datanode.getBlockScanner(),
      blockChooserImpl);
  asyncDiskService = new FsDatasetAsyncDiskService(datanode);
  asyncLazyPersistService = new RamDiskAsyncLazyPersistService(datanode);

  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    addVolume(dataLocations, storage.getStorageDir(idx));
  }
  setupAsyncLazyPersistThreads();

  cacheManager = new FsDatasetCache(this);

  // Start the lazy writer once we have built the replica maps.
  lazyWriter = new Daemon(new LazyWriter(conf));
  lazyWriter.start();
  registerMBean(datanode.getDatanodeUuid());
}

项目：hadoop-plus 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.datanode = datanode;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volsConfigured - storage.getNumStorageDirs();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  final List<FsVolumeImpl> volArray = new ArrayList<FsVolumeImpl>(
      storage.getNumStorageDirs());
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    final File dir = storage.getStorageDir(idx).getCurrentDir();
    volArray.add(new FsVolumeImpl(this, storage.getStorageID(), dir, conf));
    LOG.info("Added volume - " + dir);
  }
  volumeMap = new ReplicaMap(this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volArray, volsFailed, blockChooserImpl);
  volumes.getVolumeMap(volumeMap);

  File[] roots = new File[storage.getNumStorageDirs()];
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    roots[idx] = storage.getStorageDir(idx).getCurrentDir();
  }
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, roots);
  registerMBean(storage.getStorageID());
}

项目：FlexMap 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.fsRunning = true;
  this.datanode = datanode;
  this.dataStorage = storage;
  this.conf = conf;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);
  Collection<StorageLocation> dataLocations = DataNode.getStorageLocations(conf);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volsConfigured - storage.getNumStorageDirs();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  storageMap = new ConcurrentHashMap<String, DatanodeStorage>();
  volumeMap = new ReplicaMap(this);
  ramDiskReplicaTracker = RamDiskReplicaTracker.getInstance(conf, this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volsFailed, blockChooserImpl);
  asyncDiskService = new FsDatasetAsyncDiskService(datanode);
  asyncLazyPersistService = new RamDiskAsyncLazyPersistService(datanode);

  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    addVolume(dataLocations, storage.getStorageDir(idx));
  }
  setupAsyncLazyPersistThreads();

  cacheManager = new FsDatasetCache(this);

  // Start the lazy writer once we have built the replica maps.
  lazyWriter = new Daemon(new LazyWriter(conf));
  lazyWriter.start();
  registerMBean(datanode.getDatanodeUuid());
}

项目：hops 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf)
    throws IOException {
  this.datanode = datanode;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
      conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
          DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs =
      conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volsConfigured - storage.getNumStorageDirs();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException(
        "Invalid volume failure " + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException(
        "Too many failed volumes - " + "current valid volumes: " +
            storage.getNumStorageDirs() + ", volumes configured: " +
            volsConfigured + ", volumes failed: " + volsFailed +
            ", volume failures tolerated: " + volFailuresTolerated);
  }

  final List<FsVolumeImpl> volArray =
      new ArrayList<>(storage.getNumStorageDirs());
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    final File dir = storage.getStorageDir(idx).getCurrentDir();
    volArray.add(new FsVolumeImpl(this, storage.getStorageID(), dir, conf));
    LOG.info("Added volume - " + dir);
  }
  volumeMap = new ReplicaMap(this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl = ReflectionUtils
      .newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class, VolumeChoosingPolicy.class),
          conf);
  volumes = new FsVolumeList(volArray, volsFailed, blockChooserImpl);
  volumes.getVolumeMap(volumeMap);

  File[] roots = new File[storage.getNumStorageDirs()];
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    roots[idx] = storage.getStorageDir(idx).getCurrentDir();
  }
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, roots);
  registerMBean(storage.getStorageID());
  NUM_BUCKETS = conf.getInt(DFSConfigKeys.DFS_NUM_BUCKETS_KEY,
      DFSConfigKeys.DFS_NUM_BUCKETS_DEFAULT);
}

项目：hadoop-TCP 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.datanode = datanode;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volsConfigured - storage.getNumStorageDirs();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  final List<FsVolumeImpl> volArray = new ArrayList<FsVolumeImpl>(
      storage.getNumStorageDirs());
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    final File dir = storage.getStorageDir(idx).getCurrentDir();
    volArray.add(new FsVolumeImpl(this, storage.getStorageID(), dir, conf));
    LOG.info("Added volume - " + dir);
  }
  volumeMap = new ReplicaMap(this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volArray, volsFailed, blockChooserImpl);
  volumes.getVolumeMap(volumeMap);

  File[] roots = new File[storage.getNumStorageDirs()];
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    roots[idx] = storage.getStorageDir(idx).getCurrentDir();
  }
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, roots);
  registerMBean(storage.getStorageID());
}

项目：hardfs 文件：FsDatasetImpl.java

/**
 * An FSDataset has a directory where it loads its data files.
 */
FsDatasetImpl(DataNode datanode, DataStorage storage, Configuration conf
    ) throws IOException {
  this.datanode = datanode;
  // The number of volumes required for operation is the total number 
  // of volumes minus the number of failed volumes we can tolerate.
  final int volFailuresTolerated =
    conf.getInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY,
                DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_DEFAULT);

  String[] dataDirs = conf.getTrimmedStrings(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY);

  int volsConfigured = (dataDirs == null) ? 0 : dataDirs.length;
  int volsFailed = volsConfigured - storage.getNumStorageDirs();
  this.validVolsRequired = volsConfigured - volFailuresTolerated;

  if (volFailuresTolerated < 0 || volFailuresTolerated >= volsConfigured) {
    throw new DiskErrorException("Invalid volume failure "
        + " config value: " + volFailuresTolerated);
  }
  if (volsFailed > volFailuresTolerated) {
    throw new DiskErrorException("Too many failed volumes - "
        + "current valid volumes: " + storage.getNumStorageDirs() 
        + ", volumes configured: " + volsConfigured 
        + ", volumes failed: " + volsFailed
        + ", volume failures tolerated: " + volFailuresTolerated);
  }

  final List<FsVolumeImpl> volArray = new ArrayList<FsVolumeImpl>(
      storage.getNumStorageDirs());
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    final File dir = storage.getStorageDir(idx).getCurrentDir();
    volArray.add(new FsVolumeImpl(this, storage.getStorageID(), dir, conf));
    LOG.info("Added volume - " + dir);
  }
  volumeMap = new ReplicaMap(this);

  @SuppressWarnings("unchecked")
  final VolumeChoosingPolicy<FsVolumeImpl> blockChooserImpl =
      ReflectionUtils.newInstance(conf.getClass(
          DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
          RoundRobinVolumeChoosingPolicy.class,
          VolumeChoosingPolicy.class), conf);
  volumes = new FsVolumeList(volArray, volsFailed, blockChooserImpl);
  volumes.getVolumeMap(volumeMap);

  File[] roots = new File[storage.getNumStorageDirs()];
  for (int idx = 0; idx < storage.getNumStorageDirs(); idx++) {
    roots[idx] = storage.getStorageDir(idx).getCurrentDir();
  }
  asyncDiskService = new FsDatasetAsyncDiskService(datanode, roots);
  registerMBean(storage.getStorageID());
}