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

Class ReplicaInfo

java.lang.Object

org.apache.hadoop.hdfs.protocol.Block

org.apache.hadoop.hdfs.server.datanode.ReplicaInfo

All Implemented Interfaces:

java.lang.Comparable<org.apache.hadoop.hdfs.protocol.Block>, Replica, org.apache.hadoop.io.Writable, org.apache.hadoop.util.LightWeightGSet.LinkedElement

Direct Known Subclasses:

LocalReplica, ProvidedReplica

@Private
public abstract class ReplicaInfo
extends org.apache.hadoop.hdfs.protocol.Block
implements Replica, org.apache.hadoop.util.LightWeightGSet.LinkedElement

This class is used by datanodes to maintain meta data of its replicas. It provides a general interface for meta information of a replica.

Field Summary

Fields inherited from class org.apache.hadoop.hdfs.protocol.Block

BLOCK_FILE_PREFIX, blockFilePattern, METADATA_EXTENSION, metaFilePattern, metaOrBlockFilePattern

Method Summary

Modifier and Type	Method	Description
abstract boolean	blockDataExists()
abstract boolean	breakHardLinksIfNeeded()
abstract void	bumpReplicaGS(long newGS)	Bump a replica's generation stamp to a new one.
abstract int	compareWith(FsVolumeSpi.ScanInfo info)
abstract void	copyBlockdata(java.net.URI destination)
abstract void	copyMetadata(java.net.URI destination)
abstract ReplicaRecoveryInfo	createInfo()
abstract boolean	deleteBlockData()	Used to deletes the replica's block data.
abstract boolean	deleteMetadata()	Used to deletes the replica's metadata.
abstract long	getBlockDataLength()
abstract java.net.URI	getBlockURI()	Get the URI for where the data of this replica is stored.
long	getBytesReserved()	Number of bytes reserved for this replica on disk.
abstract java.io.InputStream	getDataInputStream(long seekOffset)	Returns an InputStream to the replica's data.
abstract java.io.OutputStream	getDataOutputStream(boolean append)	Returns an OutputStream to the replica's data.
FileIoProvider	getFileIoProvider()	Get the FileIoProvider for disk IO operations.
abstract LengthInputStream	getMetadataInputStream(long offset)	Returns an InputStream to the replica's metadata.
abstract long	getMetadataLength()
abstract java.io.OutputStream	getMetadataOutputStream(boolean append)	Returns an OutputStream to the replica's metadata.
abstract java.net.URI	getMetadataURI()	Get the URI for where the metadata of this replica is stored.
org.apache.hadoop.util.LightWeightGSet.LinkedElement	getNext()
long	getOriginalBytesReserved()	Number of bytes originally reserved for this replica.
abstract ReplicaInfo	getOriginalReplica()
abstract boolean	getPinning(org.apache.hadoop.fs.LocalFileSystem localFS)	Check whether the block was pinned.
abstract long	getRecoveryID()	Get the recovery id.
java.lang.String	getStorageUuid()	Get the storageUuid of the volume that stores this replica.
FsVolumeSpi	getVolume()	Get the volume of replica.
boolean	isOnTransientStorage()	Return true if the target volume is backed by RAM.
abstract boolean	metadataExists()
abstract boolean	renameData(java.net.URI destURI)	Rename the data URI to that referenced by destURI.
abstract boolean	renameMeta(java.net.URI destURI)	Rename the metadata URI to that referenced by destURI.
void	setNext(org.apache.hadoop.util.LightWeightGSet.LinkedElement next)
abstract void	setPinning(org.apache.hadoop.fs.LocalFileSystem localFS)	Set a block to be pinned on this datanode so that it cannot be moved by Balancer/Mover.
abstract void	setRecoveryID(long recoveryId)	Set the recovery id.
java.lang.String	toString()
abstract void	truncateBlock(long newLength)
abstract void	updateWithReplica(StorageLocation replicaLocation)	Update this replica with the StorageLocation found.

Methods inherited from class org.apache.hadoop.hdfs.protocol.Block

appendStringTo, compareTo, equals, filename2id, getBlockId, getBlockId, getBlockName, getGenerationStamp, getGenerationStamp, getNumBytes, hashCode, isBlockFilename, isMetaFilename, matchingIdAndGenStamp, metaToBlockFile, readFields, readId, set, setBlockId, setGenerationStamp, setNumBytes, toString, write, writeId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.hadoop.hdfs.server.datanode.Replica

getBlockId, getBytesOnDisk, getGenerationStamp, getNumBytes, getState, getVisibleLength

Method Detail

getVolume

public FsVolumeSpi getVolume()

Description copied from interface: Replica

Get the volume of replica.

Specified by:

getVolume in interface Replica

Returns:

the volume where this replica is located on disk

getFileIoProvider

public FileIoProvider getFileIoProvider()

Get the FileIoProvider for disk IO operations.

getStorageUuid

public java.lang.String getStorageUuid()

Get the storageUuid of the volume that stores this replica.

Specified by:

getStorageUuid in interface Replica

getBytesReserved

public long getBytesReserved()

Number of bytes reserved for this replica on disk.

getBlockURI

public abstract java.net.URI getBlockURI()

Get the URI for where the data of this replica is stored.

Returns:

URI for the location of replica data.

getDataInputStream

public abstract java.io.InputStream getDataInputStream(long seekOffset)
                                                throws java.io.IOException

Returns an InputStream to the replica's data.

Parameters:

seekOffset - the offset at which the read is started from.

Returns:

the InputStream to read the replica data.

Throws:

java.io.IOException - if an error occurs in opening a stream to the data.

getDataOutputStream

public abstract java.io.OutputStream getDataOutputStream(boolean append)
                                                  throws java.io.IOException

Returns an OutputStream to the replica's data.

Parameters:

append - indicates if the block should be opened for append.

Returns:

the OutputStream to write to the replica.

Throws:

java.io.IOException - if an error occurs in creating an OutputStream.

blockDataExists

public abstract boolean blockDataExists()

Returns:

true if the replica's data exists.

deleteBlockData

public abstract boolean deleteBlockData()

Used to deletes the replica's block data.

Returns:

true if the replica's data is successfully deleted.

getBlockDataLength

public abstract long getBlockDataLength()

Returns:

the length of the block on storage.

getMetadataURI

public abstract java.net.URI getMetadataURI()

Get the URI for where the metadata of this replica is stored.

Returns:

URI for the location of replica metadata.

getMetadataInputStream

public abstract LengthInputStream getMetadataInputStream(long offset)
                                                  throws java.io.IOException

Returns an InputStream to the replica's metadata.

Parameters:

offset - the offset at which the read is started from.

Returns:

the LengthInputStream to read the replica metadata.

Throws:

java.io.IOException

getMetadataOutputStream

public abstract java.io.OutputStream getMetadataOutputStream(boolean append)
                                                      throws java.io.IOException

Returns an OutputStream to the replica's metadata.

Parameters:

append - indicates if the block metadata should be opened for append.

Returns:

the OutputStream to write to the replica's metadata.

Throws:

java.io.IOException - if an error occurs in creating an OutputStream.

metadataExists

public abstract boolean metadataExists()

Returns:

true if the replica's metadata exists.

deleteMetadata

public abstract boolean deleteMetadata()

Used to deletes the replica's metadata.

Returns:

true if the replica's metadata is successfully deleted.

getMetadataLength

public abstract long getMetadataLength()

Returns:

the length of the metadata on storage.

renameMeta

public abstract boolean renameMeta(java.net.URI destURI)
                            throws java.io.IOException

Rename the metadata URI to that referenced by destURI.

Parameters:

destURI - the target URI.

Returns:

true if the rename is successful.

Throws:

java.io.IOException - if an exception occurs in the rename.

renameData

public abstract boolean renameData(java.net.URI destURI)
                            throws java.io.IOException

Rename the data URI to that referenced by destURI.

Parameters:

destURI - the target URI.

Returns:

true if the rename is successful.

Throws:

java.io.IOException - if an exception occurs in the rename.

updateWithReplica

public abstract void updateWithReplica(StorageLocation replicaLocation)

Update this replica with the StorageLocation found.

Parameters:

replicaLocation - the StorageLocation found for this replica.

getPinning

public abstract boolean getPinning(org.apache.hadoop.fs.LocalFileSystem localFS)
                            throws java.io.IOException

Check whether the block was pinned.

Parameters:

localFS - the local filesystem to use.

Returns:

true if the block is pinned.

Throws:

java.io.IOException

setPinning

public abstract void setPinning(org.apache.hadoop.fs.LocalFileSystem localFS)
                         throws java.io.IOException

Set a block to be pinned on this datanode so that it cannot be moved by Balancer/Mover.

Parameters:

localFS - the local filesystem to use.

Throws:

java.io.IOException - if there is an exception in the pinning.

bumpReplicaGS

public abstract void bumpReplicaGS(long newGS)
                            throws java.io.IOException

Bump a replica's generation stamp to a new one. Its on-disk meta file name is renamed to be the new one too.

Parameters:

newGS - new generation stamp

Throws:

java.io.IOException - if the change fails

getOriginalReplica

public abstract ReplicaInfo getOriginalReplica()

getRecoveryID

public abstract long getRecoveryID()

Get the recovery id.

Returns:

the generation stamp that the replica will be bumped to

setRecoveryID

public abstract void setRecoveryID(long recoveryId)

Set the recovery id.

Parameters:

recoveryId - the new recoveryId

breakHardLinksIfNeeded

public abstract boolean breakHardLinksIfNeeded()
                                        throws java.io.IOException

Throws:

java.io.IOException

createInfo

public abstract ReplicaRecoveryInfo createInfo()

compareWith

public abstract int compareWith(FsVolumeSpi.ScanInfo info)

truncateBlock

public abstract void truncateBlock(long newLength)
                            throws java.io.IOException

Throws:

java.io.IOException

copyMetadata

public abstract void copyMetadata(java.net.URI destination)
                           throws java.io.IOException

Throws:

java.io.IOException

copyBlockdata

public abstract void copyBlockdata(java.net.URI destination)
                            throws java.io.IOException

Throws:

java.io.IOException

getOriginalBytesReserved

public long getOriginalBytesReserved()

Number of bytes originally reserved for this replica. The actual reservation is adjusted as data is written to disk.

Returns:

the number of bytes originally reserved for this replica.

toString

public java.lang.String toString()

Overrides:

toString in class org.apache.hadoop.hdfs.protocol.Block

isOnTransientStorage

public boolean isOnTransientStorage()

Description copied from interface: Replica

Return true if the target volume is backed by RAM.

Specified by:

isOnTransientStorage in interface Replica

getNext

public org.apache.hadoop.util.LightWeightGSet.LinkedElement getNext()

Specified by:

getNext in interface org.apache.hadoop.util.LightWeightGSet.LinkedElement

setNext

public void setNext(org.apache.hadoop.util.LightWeightGSet.LinkedElement next)

Specified by:

setNext in interface org.apache.hadoop.util.LightWeightGSet.LinkedElement