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

Interface Summary

Interface	Description
BPServiceActorAction	Base class for BPServiceActor class Issued by BPOfferSerivce class to tell BPServiceActor to take several actions.
DataNodeMXBean	This is the JMX management interface for data node information.
DiskBalancer.BlockMover	BlockMover supports moving blocks across Volumes.
Replica	This represents block replicas which are stored in DataNode.
ReplicaInPipeline	This defines the interface of a replica in Pipeline that's being written to
ShortCircuitRegistry.Visitor

Class Summary

Class	Description
BlockPoolSliceStorage	Manages storage for the set of BlockPoolSlices which share a particular block pool id, on this DataNode.
BlockRecoveryWorker	This class handles the block recovery work commands.
BlockScanner
BlockScanner.Servlet
ChunkChecksum	holder class that holds checksum bytes and the length in a block at which the checksum bytes end ex: length = 1023 and checksum is 4 bytes which is for 512 bytes, then the checksum applies for the last chunk, or bytes 512 - 1023
DataNode	DataNode is a class (and program) that stores a set of blocks for a DFS deployment.
DataNodeFaultInjector	Used for injecting faults in DFSClient and DFSOutputStream tests.
DataNodeLayoutVersion
DatanodeUtil	Provide utility methods for Datanode.
DataSetLockManager	Class for maintain a set of lock for fsDataSetImpl.
DataStorage	Data storage information file.
DataStorage.VolumeBuilder	VolumeBuilder holds the metadata (e.g., the storage directories) of the prepared volume returned from DataStorage.prepareVolume(DataNode, StorageLocation, List).
DirectoryScanner	Periodically scans the data directories for block and block metadata files.
DirectoryScanner.BlockPoolReport	Helper class for compiling block info reports per block pool.
DirectoryScanner.ScanInfoVolumeReport	Helper class for compiling block info reports from report compiler threads.
DiskBalancer	Worker class for Disk Balancer.
DiskBalancer.DiskBalancerMover	Actual DataMover class for DiskBalancer.
DiskBalancer.VolumePair	Holds source and dest volumes UUIDs and their BasePaths that disk balancer will be operating against.
DNConf	Simple class encapsulating all of the configuration that the DataNode loads at startup time.
ErrorReportAction	A ErrorReportAction is an instruction issued by BPOfferService to BPServiceActor about a particular block encapsulated in errorMessage.
FaultInjectorFileIoEvents	Injects faults in the metadata and data related operations on datanode volumes.
FileIoProvider	This class abstracts out various file IO operations performed by the DataNode and invokes profiling (for collecting stats) and fault injection (for testing) event hooks before and after each file IO.
FinalizedProvidedReplica	This class is used for provided replicas that are finalized.
FinalizedReplica	This class describes a replica that has been finalized.
FSCachingGetSpaceUsed	Fast and accurate class to tell how much space HDFS is using.
FSCachingGetSpaceUsed.Builder	The builder class.
LocalReplica	This class is used for all replicas which are on local storage media and hence, are backed by files.
LocalReplica.ReplicaDirInfo
LocalReplicaInPipeline	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.
ProvidedReplica	This abstract class is used as a base class for provided replicas.
ReplicaBeingWritten	This class represents replicas being written.
ReplicaBuilder	This class is to be used as a builder for ReplicaInfo objects.
ReplicaHandler	This class includes a replica being actively written and the reference to the fs volume where this replica is located.
ReplicaInfo	This class is used by datanodes to maintain meta data of its replicas.
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.
ReportBadBlockAction	ReportBadBlockAction is an instruction issued by {{BPOfferService}} to {{BPServiceActor}} to report bad block to namenode
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.
ShortCircuitRegistry	Manages client short-circuit memory segments on the DataNode.
ShortCircuitRegistry.NewShmInfo
ShortCircuitRegistry.RegisteredShm
StorageLocation	Encapsulates the URI and storage medium that together describe a storage directory.
StorageLocation.CheckContext	Class to hold the parameters for running a StorageLocation.check(org.apache.hadoop.hdfs.server.datanode.StorageLocation.CheckContext).
VolumeScanner	VolumeScanner scans a single volume.
VolumeScannerCBInjector	Used for injecting call backs in VolumeScanner and BlockScanner tests.

Enum Summary

Enum	Description
DataNodeLayoutVersion.Feature	Enums for features that change the layout version.
FileIoProvider.OPERATION	Lists the types of file system operations.

Exception Summary

Exception	Description
BPServiceActorActionException
DataNode.ShortCircuitFdsUnsupportedException
DataNode.ShortCircuitFdsVersionException
DiskFileCorruptException	When kernel report a "Input/output error", we use this exception to represents some corruption(e.g.
ReplicaAlreadyExistsException	Exception indicating that the target block already exists and is not set to be recovered/overwritten.
UnexpectedReplicaStateException	Exception indicating that the replica is in an unexpected state