Package org.apache.hadoop.hdfs.server.datanode

Interface Summary

Interface	Description
DataNodeMXBean	This is the JMX management interface for data node information
Replica	This represents block replicas which are stored in DataNode.
ReplicaInPipelineInterface	This defines the interface of a replica in Pipeline that's being written to

Class Summary

Class	Description
BlockMetadataHeader	BlockMetadataHeader manages metadata for data blocks on Datanodes.
BlockPoolSliceStorage	Manages storage for the set of BlockPoolSlices which share a particular block pool id, on this DataNode.
CachingStrategy	The caching strategy we should use for an HDFS read or write operation.
DataBlockScanner	DataBlockScanner manages block scanning for all the block pools.
DataBlockScanner.Servlet
DataNode	DataNode is a class (and program) that stores a set of blocks for a DFS deployment.
DatanodeJspHelper
DatanodeUtil	Provide utility methods for Datanode.
DataStorage	Data storage information file.
DirectoryScanner	Periodically scans the data directories for block and block metadata files.
DNConf	Simple class encapsulating all of the configuration that the DataNode loads at startup time.
FinalizedReplica	This class describes a replica that has been finalized.
ReplicaBeingWritten	This class represents replicas being written.
ReplicaInfo	This class is used by datanodes to maintain meta data of its replicas.
ReplicaInfo.ReplicaDirInfo
ReplicaInPipeline	This class defines a replica in a pipeline, which includes a persistent replica being written to by a dfs client or a temporary replica being replicated by a source datanode or being copied for the balancing purpose.
ReplicaUnderRecovery	This class represents replicas that are under block recovery It has a recovery id that is equal to the generation stamp that the replica will be bumped to after recovery The recovery id is used to handle multiple concurrent block recoveries.
ReplicaWaitingToBeRecovered	This class represents a replica that is waiting to be recovered.
SecureDataNodeStarter	Utility class to start a datanode in a secure cluster, first obtaining privileged resources before main startup and handing them to the datanode.
SecureDataNodeStarter.SecureResources	Stash necessary resources needed for datanode operation in a secure env.

Exception Summary

Exception	Description
DataNode.ShortCircuitFdsUnsupportedException
DataNode.ShortCircuitFdsVersionException
ReplicaAlreadyExistsException	Exception indicating that the target block already exists and is not set to be recovered/overwritten.
ReplicaNotFoundException	Exception indicating that DataNode does not have a replica that matches the target block.