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HDFS-9314. Improve BlockPlacementPolicyDefault's picking of excess replicas. (Xiao Chen via mingma)

This commit is contained in:
Ming Ma 2015-11-24 10:30:24 -08:00
parent 1777608fa0
commit 0e54b164a8
9 changed files with 153 additions and 36 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -1676,6 +1676,9 @@ Release 2.8.0 - UNRELEASED
HDFS-7988. Replace usage of ExactSizeInputStream with LimitInputStream.
(Walter Su via wheat9)
HDFS-9314. Improve BlockPlacementPolicyDefault's picking of excess
replicas. (Xiao Chen via mingma)
OPTIMIZATIONS
HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

32
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java
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@ -916,7 +916,8 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
public DatanodeStorageInfo chooseReplicaToDelete(
Collection<DatanodeStorageInfo> moreThanOne,
Collection<DatanodeStorageInfo> exactlyOne,
final List<StorageType> excessTypes) {
final List<StorageType> excessTypes,
Map<String, List<DatanodeStorageInfo>> rackMap) {
long oldestHeartbeat =
monotonicNow() - heartbeatInterval * tolerateHeartbeatMultiplier;
DatanodeStorageInfo oldestHeartbeatStorage = null;
@ -926,7 +927,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
// Pick the node with the oldest heartbeat or with the least free space,
// if all hearbeats are within the tolerable heartbeat interval
for(DatanodeStorageInfo storage : pickupReplicaSet(moreThanOne,
exactlyOne)) {
exactlyOne, rackMap)) {
if (!excessTypes.contains(storage.getStorageType())) {
continue;
}
@ -991,7 +992,8 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
moreThanOne, exactlyOne, excessTypes)) {
cur = delNodeHintStorage;
} else { // regular excessive replica removal
cur = chooseReplicaToDelete(moreThanOne, exactlyOne, excessTypes);
cur = chooseReplicaToDelete(moreThanOne, exactlyOne, excessTypes,
rackMap);
}
firstOne = false;
if (cur == null) {
@ -1044,16 +1046,34 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
splitNodesWithRack(locs, rackMap, moreThanOne, exactlyOne);
return notReduceNumOfGroups(moreThanOne, source, target);
}
/**
* Pick up replica node set for deleting replica as over-replicated.
* First set contains replica nodes on rack with more than one
* replica while second set contains remaining replica nodes.
* So pick up first set if not empty. If first is empty, then pick second.
* If only 1 rack, pick all. If 2 racks, pick all that have more than
* 1 replicas on the same rack; if no such replicas, pick all.
* If 3 or more racks, pick all.
*/
protected Collection<DatanodeStorageInfo> pickupReplicaSet(
Collection<DatanodeStorageInfo> moreThanOne,
Collection<DatanodeStorageInfo> exactlyOne) {
return moreThanOne.isEmpty() ? exactlyOne : moreThanOne;
Collection<DatanodeStorageInfo> exactlyOne,
Map<String, List<DatanodeStorageInfo>> rackMap) {
Collection<DatanodeStorageInfo> ret = new ArrayList<>();
if (rackMap.size() == 2) {
for (List<DatanodeStorageInfo> dsi : rackMap.values()) {
if (dsi.size() >= 2) {
ret.addAll(dsi);
}
}
}
if (ret.isEmpty()) {
// Return all replicas if rackMap.size() != 2
// or rackMap.size() == 2 but no shared replicas on any rack
ret.addAll(moreThanOne);
ret.addAll(exactlyOne);
}
return ret;
}
@VisibleForTesting

8
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyRackFaultTolerant.java
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@ -169,4 +169,12 @@ public class BlockPlacementPolicyRackFaultTolerant extends BlockPlacementPolicyD
racks.add(dn.getNetworkLocation());
return new BlockPlacementStatusDefault(racks.size(), numberOfReplicas);
}
@Override
protected Collection<DatanodeStorageInfo> pickupReplicaSet(
Collection<DatanodeStorageInfo> moreThanOne,
Collection<DatanodeStorageInfo> exactlyOne,
Map<String, List<DatanodeStorageInfo>> rackMap) {
return moreThanOne.isEmpty() ? exactlyOne : moreThanOne;
}
}

3
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyWithNodeGroup.java
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@ -332,7 +332,8 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
@Override
public Collection<DatanodeStorageInfo> pickupReplicaSet(
Collection<DatanodeStorageInfo> first,
Collection<DatanodeStorageInfo> second) {
Collection<DatanodeStorageInfo> second,
Map<String, List<DatanodeStorageInfo>> rackMap) {
// If no replica within same rack, return directly.
if (first.isEmpty()) {
return second;

19
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyWithUpgradeDomain.java
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@ -206,18 +206,18 @@ public class BlockPlacementPolicyWithUpgradeDomain extends
* shareRackNotUDSet} >= 3. Removing a node from shareUDNotRackSet
* will reduce the # of racks by 1 and won't change # of upgrade
* domains.
* Note that this is different from BlockPlacementPolicyDefault which
* will keep the # of racks after deletion. With upgrade domain policy,
* given # of racks is still >= 2 after deletion, the data availability
* model remains the same as BlockPlacementPolicyDefault (only supports
* one rack failure).
* Note that this is similar to BlockPlacementPolicyDefault which
* will at most reduce the # of racks by 1, and never reduce it to < 2.
* With upgrade domain policy, given # of racks is still >= 2 after
* deletion, the data availability model remains the same as
* BlockPlacementPolicyDefault (only supports one rack failure).
* For example, assume we have 4 replicas: d1(rack1, ud1),
* d2(rack2, ud1), d3(rack3, ud3), d4(rack3, ud4). Thus we have
* shareUDNotRackSet: {d1, d2} and shareRackNotUDSet: {d3, d4}.
* With upgrade domain policy, the remaining replicas after deletion
* are {d1(or d2), d3, d4} which has 2 racks.
* With BlockPlacementPolicyDefault policy, the remaining replicas
* after deletion are {d1, d2, d3(or d4)} which has 3 racks.
* With BlockPlacementPolicyDefault policy, any of the 4 with the worst
* condition will be deleted, which in worst case has 2 racks remain.
* 3. shareUDNotRackSet isn't empty and shareRackNotUDSet is empty. This
* implies all replicas are on unique racks. Removing a node from
* shareUDNotRackSet will reduce # of racks (no different from
@ -244,7 +244,8 @@ public class BlockPlacementPolicyWithUpgradeDomain extends
@Override
protected Collection<DatanodeStorageInfo> pickupReplicaSet(
Collection<DatanodeStorageInfo> moreThanOne,
Collection<DatanodeStorageInfo> exactlyOne) {
Collection<DatanodeStorageInfo> exactlyOne,
Map<String, List<DatanodeStorageInfo>> rackMap) {
// shareUDSet includes DatanodeStorageInfo that share same upgrade
// domain with another DatanodeStorageInfo.
Collection<DatanodeStorageInfo> all = combine(moreThanOne, exactlyOne);
@ -255,7 +256,7 @@ public class BlockPlacementPolicyWithUpgradeDomain extends
List<DatanodeStorageInfo> shareRackAndUDSet = new ArrayList<>();
if (shareUDSet.size() == 0) {
// All upgrade domains are unique, use the parent set.
return super.pickupReplicaSet(moreThanOne, exactlyOne);
return super.pickupReplicaSet(moreThanOne, exactlyOne, rackMap);
} else if (moreThanOne != null) {
for (DatanodeStorageInfo storage : shareUDSet) {
if (moreThanOne.contains(storage)) {

82
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java
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@ -972,22 +972,22 @@ public class TestReplicationPolicy extends BaseReplicationPolicyTest {
// test returning null
excessTypes.add(StorageType.SSD);
assertNull(((BlockPlacementPolicyDefault) replicator)
.chooseReplicaToDelete(first, second, excessTypes));
.chooseReplicaToDelete(first, second, excessTypes, rackMap));
}
excessTypes.add(StorageType.DEFAULT);
DatanodeStorageInfo chosen = ((BlockPlacementPolicyDefault) replicator)
.chooseReplicaToDelete(first, second, excessTypes);
// Within first set, storages[1] with less free space
assertEquals(chosen, storages[1]);
.chooseReplicaToDelete(first, second, excessTypes, rackMap);
// Within all storages, storages[5] with least free space
assertEquals(chosen, storages[5]);
replicator.adjustSetsWithChosenReplica(rackMap, first, second, chosen);
assertEquals(0, first.size());
assertEquals(3, second.size());
// Within second set, storages[5] with less free space
assertEquals(2, first.size());
assertEquals(1, second.size());
// Within first set, storages[1] with less free space
excessTypes.add(StorageType.DEFAULT);
chosen = ((BlockPlacementPolicyDefault) replicator).chooseReplicaToDelete(
first, second, excessTypes);
assertEquals(chosen, storages[5]);
first, second, excessTypes, rackMap);
assertEquals(chosen, storages[1]);
}
@Test
@ -1032,17 +1032,15 @@ public class TestReplicationPolicy extends BaseReplicationPolicyTest {
excessTypes, storages[3].getDatanodeDescriptor(), null);
assertTrue(excessReplicas.contains(excessStorage));
// The block was initially created on excessSSD(rack r1),
// storages[4](rack r3) and storages[5](rack r3) with
// ONESSD_STORAGE_POLICY_NAME storage policy.
// ONESSD_STORAGE_POLICY_NAME storage policy. Replication factor = 3.
// Right after balancer moves the block from storages[5] to
// storages[3](rack r2), the application changes the storage policy from
// ONESSD_STORAGE_POLICY_NAME to HOT_STORAGE_POLICY_ID. In this case,
// no replica can be chosen as the excessive replica as
// chooseReplicasToDelete only considers storages[4] and storages[5] that
// are the same rack. But neither's storage type is SSD.
// TODO BlockPlacementPolicyDefault should be able to delete excessSSD.
// we should be able to delete excessSSD since the remaining
// storages ({storages[3]}, {storages[4], storages[5]})
// are on different racks (r2, r3).
nonExcess.clear();
nonExcess.add(excessSSD);
nonExcess.add(storages[3]);
@ -1053,7 +1051,59 @@ public class TestReplicationPolicy extends BaseReplicationPolicyTest {
excessReplicas = replicator.chooseReplicasToDelete(nonExcess, 3,
excessTypes, storages[3].getDatanodeDescriptor(),
storages[5].getDatanodeDescriptor());
assertTrue(excessReplicas.size() == 0);
assertEquals(1, excessReplicas.size());
assertTrue(excessReplicas.contains(excessSSD));
// Similar to above, but after policy change and before deletion,
// the replicas are located on excessSSD(rack r1), storages[1](rack r1),
// storages[2](rack r2) and storages[3](rack r2). Replication factor = 3.
// In this case, we should be able to delete excessSSD since the remaining
// storages ({storages[1]} , {storages[2], storages[3]})
// are on different racks (r1, r2).
nonExcess.clear();
nonExcess.add(excessSSD);
nonExcess.add(storages[1]);
nonExcess.add(storages[2]);
nonExcess.add(storages[3]);
excessTypes = storagePolicy.chooseExcess((short) 3,
DatanodeStorageInfo.toStorageTypes(nonExcess));
excessReplicas = replicator.chooseReplicasToDelete(nonExcess, 3,
excessTypes, storages[1].getDatanodeDescriptor(),
storages[3].getDatanodeDescriptor());
assertEquals(1, excessReplicas.size());
assertTrue(excessReplicas.contains(excessSSD));
// Similar to above, but after policy change and before deletion,
// the replicas are located on excessSSD(rack r1), storages[2](rack r2)
// Replication factor = 1. We should be able to delete excessSSD.
nonExcess.clear();
nonExcess.add(excessSSD);
nonExcess.add(storages[2]);
excessTypes = storagePolicy.chooseExcess((short) 1,
DatanodeStorageInfo.toStorageTypes(nonExcess));
excessReplicas = replicator.chooseReplicasToDelete(nonExcess, 1,
excessTypes, storages[2].getDatanodeDescriptor(), null);
assertEquals(1, excessReplicas.size());
assertTrue(excessReplicas.contains(excessSSD));
// The block was initially created on excessSSD(rack r1),
// storages[4](rack r3) and storages[5](rack r3) with
// ONESSD_STORAGE_POLICY_NAME storage policy. Replication factor = 2.
// In this case, no replica can be chosen as the excessive replica by
// chooseReplicasToDelete because if the SSD storage is deleted,
// the remaining storages[4] and storages[5] are the same rack (r3),
// violating block placement policy (i.e. the number of racks >= 2).
// TODO BlockPlacementPolicyDefault should be able to rebalance the replicas
// and then delete excessSSD.
nonExcess.clear();
nonExcess.add(excessSSD);
nonExcess.add(storages[4]);
nonExcess.add(storages[5]);
excessTypes = storagePolicy.chooseExcess((short) 2,
DatanodeStorageInfo.toStorageTypes(nonExcess));
excessReplicas = replicator.chooseReplicasToDelete(nonExcess, 2,
excessTypes, null, null);
assertEquals(0, excessReplicas.size());
}
@Test

6
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicyWithNodeGroup.java
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@ -544,7 +544,7 @@ public class TestReplicationPolicyWithNodeGroup extends BaseReplicationPolicyTes
List<StorageType> excessTypes = new ArrayList<>();
excessTypes.add(StorageType.DEFAULT);
DatanodeStorageInfo chosen = ((BlockPlacementPolicyDefault) replicator)
.chooseReplicaToDelete(first, second, excessTypes);
.chooseReplicaToDelete(first, second, excessTypes, rackMap);
// Within first set {dataNodes[0], dataNodes[1], dataNodes[2]},
// dataNodes[0] and dataNodes[1] are in the same nodegroup,
// but dataNodes[1] is chosen as less free space
@ -557,7 +557,7 @@ public class TestReplicationPolicyWithNodeGroup extends BaseReplicationPolicyTes
// as less free space
excessTypes.add(StorageType.DEFAULT);
chosen = ((BlockPlacementPolicyDefault) replicator).chooseReplicaToDelete(
first, second, excessTypes);
first, second, excessTypes, rackMap);
assertEquals(chosen, storages[2]);
replicator.adjustSetsWithChosenReplica(rackMap, first, second, chosen);
@ -566,7 +566,7 @@ public class TestReplicationPolicyWithNodeGroup extends BaseReplicationPolicyTes
// Within second set, dataNodes[5] with less free space
excessTypes.add(StorageType.DEFAULT);
chosen = ((BlockPlacementPolicyDefault) replicator).chooseReplicaToDelete(
first, second, excessTypes);
first, second, excessTypes, rackMap);
assertEquals(chosen, storages[5]);
}

32
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicyWithUpgradeDomain.java
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@ -389,6 +389,38 @@ public class TestReplicationPolicyWithUpgradeDomain
assertTrue(excessReplicas.size() == 2);
assertTrue(excessReplicas.contains(storages[0]));
assertTrue(excessReplicas.contains(excessStorage));
// Test SSD related deletion. With different rack settings here, but
// similar to {@link TestReplicationPolicy#testChooseReplicasToDelete}.
// The block was initially created on excessSSD(rack r1, UD 4),
// storages[7](rack r3, UD 2) and storages[8](rack r3, UD 3) with
// ONESSD_STORAGE_POLICY_NAME storage policy. Replication factor = 3.
// Right after balancer moves the block from storages[7] to
// storages[3](rack r2, UD 1), the application changes the storage policy
// from ONESSD_STORAGE_POLICY_NAME to HOT_STORAGE_POLICY_ID. In this case,
// we should be able to delete excessSSD since the remaining
// storages ({storages[3]}, {storages[7], storages[8]})
// are on different racks (r2, r3) and different UDs (1, 2, 3).
DatanodeStorageInfo excessSSD = DFSTestUtil.createDatanodeStorageInfo(
"Storage-excess-SSD-ID", "localhost",
storages[0].getDatanodeDescriptor().getNetworkLocation(), "foo.com",
StorageType.SSD, null);
DatanodeStorageInfo[] ssds = { excessSSD };
DatanodeDescriptor ssdNodes[] = DFSTestUtil.toDatanodeDescriptor(ssds);
ssdNodes[0].setUpgradeDomain(Integer.toString(4));
nonExcess.clear();
nonExcess.add(excessSSD);
nonExcess.add(storages[3]);
nonExcess.add(storages[7]);
nonExcess.add(storages[8]);
excessTypes = storagePolicy.chooseExcess((short) 3,
DatanodeStorageInfo.toStorageTypes(nonExcess));
excessReplicas = replicator.chooseReplicasToDelete(nonExcess, 3,
excessTypes, storages[3].getDatanodeDescriptor(),
storages[7].getDatanodeDescriptor());
assertEquals(1, excessReplicas.size());
assertTrue(excessReplicas.contains(excessSSD));
}
@Test

4
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestDNFencing.java
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@ -23,6 +23,7 @@ import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadLocalRandom;
@ -633,7 +634,8 @@ public class TestDNFencing {
public DatanodeStorageInfo chooseReplicaToDelete(
Collection<DatanodeStorageInfo> moreThanOne,
Collection<DatanodeStorageInfo> exactlyOne,
List<StorageType> excessTypes) {
List<StorageType> excessTypes,
Map<String, List<DatanodeStorageInfo>> rackMap) {
Collection<DatanodeStorageInfo> chooseFrom = !moreThanOne.isEmpty() ?
moreThanOne : exactlyOne;