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HDFS-8946. Improve choosing datanode storage for block placement. (yliu)

This commit is contained in:
yliu 2015-09-01 08:52:50 +08:00
parent 4eaa7fd3ea
commit 8fa41d9dd4
4 changed files with 93 additions and 118 deletions
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2
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -870,6 +870,8 @@ Release 2.8.0 - UNRELEASED
HDFS-8990. Move RemoteBlockReader to hdfs-client module.
(Mingliang via wheat9)
HDFS-8946. Improve choosing datanode storage for block placement. (yliu)
OPTIMIZATIONS
HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

127
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java
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@ -26,12 +26,9 @@ import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage.State;
import org.apache.hadoop.net.NetworkTopology;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.net.NodeBase;
@ -458,11 +455,11 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
for (Iterator<Map.Entry<StorageType, Integer>> iter = storageTypes
.entrySet().iterator(); iter.hasNext(); ) {
Map.Entry<StorageType, Integer> entry = iter.next();
for (DatanodeStorageInfo localStorage : DFSUtil.shuffle(
localDatanode.getStorageInfos())) {
StorageType type = entry.getKey();
if (addIfIsGoodTarget(localStorage, excludedNodes, blocksize,
results, type) >= 0) {
DatanodeStorageInfo localStorage = chooseStorage4Block(
localDatanode, blocksize, results, entry.getKey());
if (localStorage != null) {
// add node and related nodes to excludedNode
addToExcludedNodes(localDatanode, excludedNodes);
int num = entry.getValue();
if (num == 1) {
iter.remove();
@ -474,7 +471,6 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
}
}
}
}
return null;
}
@ -669,49 +665,39 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
builder.append("\nNode ").append(NodeBase.getPath(chosenNode)).append(" [");
}
numOfAvailableNodes--;
if (!isGoodDatanode(chosenNode, maxNodesPerRack, considerLoad,
DatanodeStorageInfo storage = null;
if (isGoodDatanode(chosenNode, maxNodesPerRack, considerLoad,
results, avoidStaleNodes)) {
if (LOG.isDebugEnabled()) {
builder.append("\n]");
}
badTarget = true;
continue;
}
final DatanodeStorageInfo[] storages = DFSUtil.shuffle(
chosenNode.getStorageInfos());
int i = 0;
boolean search = true;
for (Iterator<Map.Entry<StorageType, Integer>> iter = storageTypes
.entrySet().iterator(); search && iter.hasNext(); ) {
.entrySet().iterator(); iter.hasNext(); ) {
Map.Entry<StorageType, Integer> entry = iter.next();
for (i = 0; i < storages.length; i++) {
StorageType type = entry.getKey();
final int newExcludedNodes = addIfIsGoodTarget(storages[i],
excludedNodes, blocksize, results, type);
if (newExcludedNodes >= 0) {
storage = chooseStorage4Block(
chosenNode, blocksize, results, entry.getKey());
if (storage != null) {
numOfReplicas--;
if (firstChosen == null) {
firstChosen = storages[i];
firstChosen = storage;
}
numOfAvailableNodes -= newExcludedNodes;
// add node and related nodes to excludedNode
numOfAvailableNodes -=
addToExcludedNodes(chosenNode, excludedNodes);
int num = entry.getValue();
if (num == 1) {
iter.remove();
} else {
entry.setValue(num - 1);
}
search = false;
break;
}
}
}
if (LOG.isDebugEnabled()) {
builder.append("\n]");
}
// If no candidate storage was found on this DN then set badTarget.
badTarget = (i == storages.length);
badTarget = (storage == null);
}
}
@ -740,32 +726,27 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
}
/**
* If the given storage is a good target, add it to the result list and
* update the set of excluded nodes.
* @return -1 if the given is not a good target;
* otherwise, return the number of nodes added to excludedNodes set.
* Choose a good storage of given storage type from datanode, and add it to
* the result list.
*
* @param dnd datanode descriptor
* @param blockSize requested block size
* @param results the result storages
* @param storageType requested storage type
* @return the chosen datanode storage
*/
int addIfIsGoodTarget(DatanodeStorageInfo storage,
Set<Node> excludedNodes,
DatanodeStorageInfo chooseStorage4Block(DatanodeDescriptor dnd,
long blockSize,
List<DatanodeStorageInfo> results,
StorageType storageType) {
if (isGoodTarget(storage, blockSize, results, storageType)) {
DatanodeStorageInfo storage =
dnd.chooseStorage4Block(storageType, blockSize);
if (storage != null) {
results.add(storage);
// add node and related nodes to excludedNode
return addToExcludedNodes(storage.getDatanodeDescriptor(), excludedNodes);
} else {
return -1;
}
}
private static void logNodeIsNotChosen(DatanodeStorageInfo storage, String reason) {
if (LOG.isDebugEnabled()) {
// build the error message for later use.
debugLoggingBuilder.get()
.append("\n Storage ").append(storage)
.append(" is not chosen since ").append(reason).append(".");
logNodeIsNotChosen(dnd, "no good storage to place the block ");
}
return storage;
}
private static void logNodeIsNotChosen(DatanodeDescriptor node,
@ -836,52 +817,6 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
return true;
}
/**
* Determine if a storage is a good target.
*
* @param storage The target storage
* @param blockSize Size of block
* @param results A list containing currently chosen nodes. Used to check if
* too many nodes has been chosen in the target rack.
* @return Return true if <i>node</i> has enough space.
*/
private boolean isGoodTarget(DatanodeStorageInfo storage,
long blockSize,
List<DatanodeStorageInfo> results,
StorageType requiredStorageType) {
if (storage.getStorageType() != requiredStorageType) {
logNodeIsNotChosen(storage, "storage types do not match,"
+ " where the required storage type is " + requiredStorageType);
return false;
}
if (storage.getState() == State.READ_ONLY_SHARED) {
logNodeIsNotChosen(storage, "storage is read-only");
return false;
}
if (storage.getState() == State.FAILED) {
logNodeIsNotChosen(storage, "storage has failed");
return false;
}
DatanodeDescriptor node = storage.getDatanodeDescriptor();
final long requiredSize = blockSize * HdfsServerConstants.MIN_BLOCKS_FOR_WRITE;
final long scheduledSize = blockSize * node.getBlocksScheduled(storage.getStorageType());
final long remaining = node.getRemaining(storage.getStorageType(),
requiredSize);
if (requiredSize > remaining - scheduledSize) {
logNodeIsNotChosen(storage, "the node does not have enough "
+ storage.getStorageType() + " space"
+ " (required=" + requiredSize
+ ", scheduled=" + scheduledSize
+ ", remaining=" + remaining + ")");
return false;
}
return true;
}
/**
* Return a pipeline of nodes.
* The pipeline is formed finding a shortest path that

36
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java
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@ -31,14 +31,15 @@ import java.util.Queue;
import java.util.Set;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
import org.apache.hadoop.hdfs.server.namenode.CachedBlock;
import org.apache.hadoop.hdfs.server.protocol.BlockReportContext;
import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
@ -663,26 +664,39 @@ public class DatanodeDescriptor extends DatanodeInfo {
}
/**
* Return the sum of remaining spaces of the specified type. If the remaining
* space of a storage is less than minSize, it won't be counted toward the
* sum.
* Find whether the datanode contains good storage of given type to
* place block of size <code>blockSize</code>.
*
* @param t The storage type. If null, the type is ignored.
* @param minSize The minimum free space required.
* @return the sum of remaining spaces that are bigger than minSize.
* <p>Currently datanode only cares about the storage type, in this
* method, the first storage of given type we see is returned.
*
* @param t requested storage type
* @param blockSize requested block size
* @return
*/
public long getRemaining(StorageType t, long minSize) {
public DatanodeStorageInfo chooseStorage4Block(StorageType t,
long blockSize) {
final long requiredSize =
blockSize * HdfsServerConstants.MIN_BLOCKS_FOR_WRITE;
final long scheduledSize = blockSize * getBlocksScheduled(t);
long remaining = 0;
DatanodeStorageInfo storage = null;
for (DatanodeStorageInfo s : getStorageInfos()) {
if (s.getState() == State.NORMAL &&
(t == null || s.getStorageType() == t)) {
s.getStorageType() == t) {
if (storage == null) {
storage = s;
}
long r = s.getRemaining();
if (r >= minSize) {
if (r >= requiredSize) {
remaining += r;
}
}
}
return remaining;
if (requiredSize > remaining - scheduledSize) {
return null;
}
return storage;
}
/**

26
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java
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@ -181,7 +181,7 @@ public class TestReplicationPolicy {
* considered.
*/
@Test
public void testChooseNodeWithMultipleStorages() throws Exception {
public void testChooseNodeWithMultipleStorages1() throws Exception {
updateHeartbeatWithUsage(dataNodes[5],
2* HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L,
(2*HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE)/3, 0L,
@ -200,6 +200,30 @@ public class TestReplicationPolicy {
resetHeartbeatForStorages();
}
/**
* Test whether all storages on the datanode are considered while
* choosing target to place block.
*/
@Test
public void testChooseNodeWithMultipleStorages2() throws Exception {
updateHeartbeatWithUsage(dataNodes[5],
2* HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L,
(2*HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE)/3, 0L,
0L, 0L, 0, 0);
updateHeartbeatForExtraStorage(
2* HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L,
HdfsServerConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L);
DatanodeStorageInfo[] targets;
targets = chooseTarget (1, dataNodes[5],
new ArrayList<DatanodeStorageInfo>(), null);
assertEquals(1, targets.length);
assertEquals(dataNodes[5], targets[0].getDatanodeDescriptor());
resetHeartbeatForStorages();
}
/**
* In this testcase, client is dataNodes[0]. So the 1st replica should be
* placed on dataNodes[0], the 2nd replica should be placed on