Package org.apache.hadoop.hdfs.server.namenode

Class ErasureCodingPolicyManager

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.ErasureCodingPolicyManager

@LimitedPrivate("HDFS")
public final class ErasureCodingPolicyManager
extends java.lang.Object

This manages erasure coding policies predefined and activated in the system. It loads customized policies and syncs with persisted ones in NameNode image. This class is instantiated by the FSNamesystem.

Field Summary

Fields

Modifier and Type	Field	Description
static org.slf4j.Logger	LOG

Method Summary

Modifier and Type	Method	Description
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy	addPolicy(org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy policy)	Add an erasure coding policy.
static boolean	checkStoragePolicySuitableForECStripedMode(byte storagePolicyID)
void	clear()	Clear and clean up.
boolean	disablePolicy(java.lang.String name)	Disable an erasure coding policy by policyName.
boolean	enablePolicy(java.lang.String name)	Enable an erasure coding policy by policyName.
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy	getByID(byte id)	Get a ErasureCodingPolicy by policy ID, including system policy and user defined policy.
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy	getByName(java.lang.String name)	Get a ErasureCodingPolicy by policy name, including system policy and user defined policy.
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy[]	getCopyOfEnabledPolicies()
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy[]	getEnabledPolicies()	Get the set of enabled policies.
java.lang.String	getEnabledPoliciesMetric()
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy	getEnabledPolicyByName(java.lang.String name)	Get enabled policy by policy name.
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy	getErasureCodingPolicyByName(java.lang.String name)	Get a ErasureCodingPolicy by policy name, including system policy, user defined policy and Replication policy.
static ErasureCodingPolicyManager	getInstance()
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo[]	getPersistedPolicies()	Get all system defined policies and user defined policies as it is written out in the fsimage.
org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo[]	getPolicies()	Get all system defined policies and user defined policies.
java.util.List<org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy>	getRemovedPolicies()
void	init(org.apache.hadoop.conf.Configuration conf)
void	loadPolicies(java.util.List<org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo> ecPolicies, org.apache.hadoop.conf.Configuration conf)	Reload erasure coding policies from fsImage.
void	removePolicy(java.lang.String name)	Remove an User erasure coding policy by policyName.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static org.slf4j.Logger LOG

Method Detail

getInstance

public static ErasureCodingPolicyManager getInstance()

init

public void init(org.apache.hadoop.conf.Configuration conf)
          throws java.io.IOException

Throws:

java.io.IOException

getEnabledPolicies

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy[] getEnabledPolicies()

Get the set of enabled policies.

Returns:

all policies

getEnabledPolicyByName

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy getEnabledPolicyByName(java.lang.String name)

Get enabled policy by policy name.

checkStoragePolicySuitableForECStripedMode

public static boolean checkStoragePolicySuitableForECStripedMode(byte storagePolicyID)

Returns:

if the specified storage policy ID is suitable for striped EC files.

getPolicies

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo[] getPolicies()

Get all system defined policies and user defined policies.

Returns:

all policies

getPersistedPolicies

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo[] getPersistedPolicies()

Get all system defined policies and user defined policies as it is written out in the fsimage. The difference between persisted policies and all policies is that if a default policy is only enabled at startup, it will appear as disabled in the persisted policy list and in the fsimage.

Returns:

persisted policies

getCopyOfEnabledPolicies

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy[] getCopyOfEnabledPolicies()

getByID

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy getByID(byte id)

Get a ErasureCodingPolicy by policy ID, including system policy and user defined policy.

Returns:

ecPolicy, or null if not found

getByName

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy getByName(java.lang.String name)

Get a ErasureCodingPolicy by policy name, including system policy and user defined policy.

Returns:

ecPolicy, or null if not found

getErasureCodingPolicyByName

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy getErasureCodingPolicyByName(java.lang.String name)

Get a ErasureCodingPolicy by policy name, including system policy, user defined policy and Replication policy.

Returns:

ecPolicy, or null if not found

clear

public void clear()

Clear and clean up.

addPolicy

public org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy addPolicy(org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy policy)

Add an erasure coding policy.

Returns:

the added policy

removePolicy

public void removePolicy(java.lang.String name)

Remove an User erasure coding policy by policyName.

getRemovedPolicies

@VisibleForTesting
public java.util.List<org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy> getRemovedPolicies()

disablePolicy

public boolean disablePolicy(java.lang.String name)

Disable an erasure coding policy by policyName.

enablePolicy

public boolean enablePolicy(java.lang.String name)

Enable an erasure coding policy by policyName.

loadPolicies

public void loadPolicies(java.util.List<org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo> ecPolicies,
                         org.apache.hadoop.conf.Configuration conf)
                  throws java.io.IOException

Reload erasure coding policies from fsImage.

Parameters:

ecPolicies - contains ErasureCodingPolicy list

Throws:

java.io.IOException

getEnabledPoliciesMetric

public java.lang.String getEnabledPoliciesMetric()