org.apache.hadoop.hdfs.server.namenode

类 FSImage

java.lang.Object

org.apache.hadoop.hdfs.server.common.StorageInfo

org.apache.hadoop.hdfs.server.common.Storage

org.apache.hadoop.hdfs.server.namenode.FSImage

public class FSImage
extends Storage

FSImage handles checkpointing and logging of the namespace edits.

嵌套类概要

从类继承的嵌套类/接口 org.apache.hadoop.hdfs.server.common.Storage

Storage.StorageDirectory, Storage.StorageDirType, Storage.StorageState

字段概要

字段

限定符和类型	字段和说明
protected long	checkpointTime
protected FSEditLog	editLog

从类继承的字段 org.apache.hadoop.hdfs.server.common.Storage

LAST_PRE_UPGRADE_LAYOUT_VERSION, LAST_UPGRADABLE_HADOOP_VERSION, LAST_UPGRADABLE_LAYOUT_VERSION, LAYOUT_VERSIONS_203, LOG, PRE_GENERATIONSTAMP_LAYOUT_VERSION, STORAGE_DIR_CURRENT, STORAGE_FILE_VERSION, storageDirs

从类继承的字段 org.apache.hadoop.hdfs.server.common.StorageInfo

cTime, layoutVersion, namespaceID

构造器概要

构造器

构造器和说明
FSImage(File imageDir) Represents an Image (image and edit file).
FSImage(StorageInfo storageInfo)

方法概要

方法

限定符和类型	方法和说明
protected void	corruptPreUpgradeStorage(File rootDir)
void	format()
FSEditLog	getEditLog()
protected void	getFields(Properties props, Storage.StorageDirectory sd) Get common storage fields.
File	getFsEditName()
boolean	isConversionNeeded(Storage.StorageDirectory sd)
protected void	moveCurrent(Storage.StorageDirectory sd) Move current to lastcheckpoint.tmp and recreate empty current.
protected void	moveLastCheckpoint(Storage.StorageDirectory sd) Move lastcheckpoint.tmp to previous.checkpoint
static byte[]	readBytes(DataInputStream in)
static String	readString(DataInputStream in)
protected void	saveCurrent(Storage.StorageDirectory sd) Save current image and empty journal into current directory.
void	setEditLog(FSEditLog newLog) Testing hook
protected void	setFields(Properties props, Storage.StorageDirectory sd) Write last checkpoint time and version file into the storage directory.

从类继承的方法 org.apache.hadoop.hdfs.server.common.Storage

addStorageDir, checkVersionUpgradable, deleteDir, dirIterator, dirIterator, getNumStorageDirs, getRegistrationID, getStorageDir, is203LayoutVersion, isLockSupported, rename, unlockAll, writeAll, writeCorruptedData

从类继承的方法 org.apache.hadoop.hdfs.server.common.StorageInfo

getCTime, getLayoutVersion, getNamespaceID, setStorageInfo

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料

checkpointTime

protected long checkpointTime

editLog

protected FSEditLog editLog

构造器详细资料

FSImage

public FSImage(StorageInfo storageInfo)

FSImage

public FSImage(File imageDir)
        throws IOException

Represents an Image (image and edit file).

抛出:

IOException

方法详细资料

getFields

protected void getFields(Properties props,
             Storage.StorageDirectory sd)
                  throws IOException

从类复制的说明: Storage

Get common storage fields. Should be overloaded if additional fields need to be get.

覆盖:

getFields 在类中 Storage

抛出:

IOException

setFields

protected void setFields(Properties props,
             Storage.StorageDirectory sd)
                  throws IOException

Write last checkpoint time and version file into the storage directory. The version file should always be written last. Missing or corrupted version file indicates that the checkpoint is not valid.

覆盖:

setFields 在类中 Storage

参数:

sd - storage directory

抛出:

IOException

getEditLog

public FSEditLog getEditLog()

setEditLog

public void setEditLog(FSEditLog newLog)

Testing hook

isConversionNeeded

public boolean isConversionNeeded(Storage.StorageDirectory sd)
                           throws IOException

指定者:

isConversionNeeded 在类中 Storage

抛出:

IOException

saveCurrent

protected void saveCurrent(Storage.StorageDirectory sd)
                    throws IOException

Save current image and empty journal into current directory.

抛出:

IOException

moveCurrent

protected void moveCurrent(Storage.StorageDirectory sd)
                    throws IOException

Move current to lastcheckpoint.tmp and recreate empty current. current is moved only if it is well formatted, that is contains VERSION file.

抛出:

IOException

另请参阅:

Storage.StorageDirectory.getLastCheckpointTmp(), Storage.StorageDirectory.getPreviousCheckpoint()

moveLastCheckpoint

protected void moveLastCheckpoint(Storage.StorageDirectory sd)
                           throws IOException

Move lastcheckpoint.tmp to previous.checkpoint

抛出:

IOException

另请参阅:

Storage.StorageDirectory.getPreviousCheckpoint(), Storage.StorageDirectory.getLastCheckpointTmp()

format

public void format()
            throws IOException

抛出:

IOException

getFsEditName

public File getFsEditName()
                   throws IOException

抛出:

IOException

corruptPreUpgradeStorage

protected void corruptPreUpgradeStorage(File rootDir)
                                 throws IOException

指定者:

corruptPreUpgradeStorage 在类中 Storage

抛出:

IOException

readString

public static String readString(DataInputStream in)
                         throws IOException

抛出:

IOException

readBytes

public static byte[] readBytes(DataInputStream in)
                        throws IOException

抛出:

IOException