Package org.apache.hadoop.io.erasurecode.coder

Class HHXORErasureEncoder

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.io.erasurecode.coder.ErasureEncoder

org.apache.hadoop.io.erasurecode.coder.HHXORErasureEncoder

All Implemented Interfaces:

Configurable, ErasureCoder

@Private
public class HHXORErasureEncoder
extends ErasureEncoder

Hitchhiker is a new erasure coding algorithm developed as a research project at UC Berkeley by Rashmi Vinayak. It has been shown to reduce network traffic and disk I/O by 25%-45% during data reconstruction while retaining the same storage capacity and failure tolerance capability of RS codes. The Hitchhiker algorithm is described in K.V.Rashmi, et al., "A "Hitchhiker's" Guide to Fast and Efficient Data Reconstruction in Erasure-coded Data Centers", in ACM SIGCOMM 2014. This is Hitchhiker-XOR erasure encoder that encodes a block group.

Constructor Summary

Constructors

Constructor	Description
HHXORErasureEncoder(ErasureCoderOptions options)

Method Summary

Modifier and Type	Method	Description
protected ErasureCodingStep	prepareEncodingStep(ECBlockGroup blockGroup)	Perform encoding against a block group.
void	release()	Release the resources if any.

Methods inherited from class org.apache.hadoop.io.erasurecode.coder.ErasureEncoder

calculateCoding, getInputBlocks, getNumDataUnits, getNumParityUnits, getOptions, getOutputBlocks, preferDirectBuffer

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Constructor Details

HHXORErasureEncoder

public HHXORErasureEncoder(ErasureCoderOptions options)

Method Details

prepareEncodingStep

protected ErasureCodingStep prepareEncodingStep(ECBlockGroup blockGroup)

Description copied from class: ErasureEncoder

Perform encoding against a block group.

Specified by:

prepareEncodingStep in class ErasureEncoder

Parameters:

blockGroup - blockGroup.

Returns:

encoding step for caller to do the real work

release

public void release()

Description copied from interface: ErasureCoder

Release the resources if any. Good chance to invoke RawErasureCoder#release.

Specified by:

release in interface ErasureCoder

Overrides:

release in class ErasureEncoder