alluxio.master.journal.ufs

Class UfsJournalSystem

java.lang.Object

alluxio.master.journal.AbstractJournalSystem

alluxio.master.journal.ufs.UfsJournalSystem

All Implemented Interfaces:

JournalSystem

@NotThreadSafe
public class UfsJournalSystem
extends AbstractJournalSystem

Factory for under file storage journals.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.master.journal.JournalSystem

JournalSystem.Builder, JournalSystem.Mode

Constructor Summary

Constructors

Constructor and Description
UfsJournalSystem(URI base, long quietTimeMs) Creates a UFS journal system with the specified base location.

Method Summary

Modifier and Type	Method and Description
void	checkpoint() Creates a checkpoint in the primary master journal system.
UfsJournal	createJournal(Master master) Creates a journal for the given state machine.
void	format() Formats the journal system.
void	gainPrimacy() Transitions the journal to primary mode.
boolean	isEmpty() Returns whether the journal is formatted and has not had any entries written to it yet.
boolean	isFormatted()
void	losePrimacy() Transitions the journal to secondary mode.
void	startInternal() Starts the journal system.
void	stopInternal() Stops the journal system.

Methods inherited from class alluxio.master.journal.AbstractJournalSystem

addJournalSink, getJournalSinks, removeJournalSink, start, stop

Methods inherited from class java.lang.Object

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

Constructor Detail

UfsJournalSystem

public UfsJournalSystem(URI base,
                        long quietTimeMs)

Creates a UFS journal system with the specified base location. When journals are created, their names are appended to the base location. The created journals all function independently.

Parameters:

base - the base location for journals created by this factory

quietTimeMs - before upgrading from SECONDARY to PRIMARY mode, the journal will wait until this duration has passed without any journal entries being written.

Method Detail

createJournal

public UfsJournal createJournal(Master master)

Description copied from interface: JournalSystem

Creates a journal for the given state machine. The returned journal can create journal contexts for writing journal entries. However, no entries may be written until the journal system has been started, and entries may only be written when the journal system is in PRIMARY mode. When the journal is started in secondary mode, it will call Journaled#processJournalEntry(JournalEntry) and Journaled.resetState() to keep the state machine's state in sync with the entries written to the journal.

Parameters:

master - the master to create the journal for

Returns:

a new instance of Journal

gainPrimacy

public void gainPrimacy()

Description copied from interface: JournalSystem

Transitions the journal to primary mode.

losePrimacy

public void losePrimacy()

Description copied from interface: JournalSystem

Transitions the journal to secondary mode.

startInternal

public void startInternal()
                   throws IOException

Description copied from class: AbstractJournalSystem

Starts the journal system.

Specified by:

startInternal in class AbstractJournalSystem

Throws:

IOException

stopInternal

public void stopInternal()

Description copied from class: AbstractJournalSystem

Stops the journal system.

Specified by:

stopInternal in class AbstractJournalSystem

isFormatted

public boolean isFormatted()
                    throws IOException

Returns:

whether the journal system has been formatted

Throws:

IOException

isEmpty

public boolean isEmpty()

Description copied from interface: JournalSystem

Returns whether the journal is formatted and has not had any entries written to it yet. This can only be determined when the journal system is in primary mode because entries are written to the primary first.

Returns:

whether the journal system is freshly formatted

format

public void format()
            throws IOException

Description copied from interface: JournalSystem

Formats the journal system.

Throws:

IOException

checkpoint

public void checkpoint()
                throws IOException

Description copied from interface: JournalSystem

Creates a checkpoint in the primary master journal system.

Throws:

IOException