/// <summary>
/// The test verifies the number of outstanding replication requests for a
/// given DN shouldn't exceed the limit set by configuration property
/// dfs.namenode.replication.max-streams-hard-limit.
/// </summary>
/// <remarks>
/// The test verifies the number of outstanding replication requests for a
/// given DN shouldn't exceed the limit set by configuration property
/// dfs.namenode.replication.max-streams-hard-limit.
/// The test does the followings:
/// 1. Create a mini cluster with 2 DNs. Set large heartbeat interval so that
/// replication requests won't be picked by any DN right away.
/// 2. Create a file with 10 blocks and replication factor 2. Thus each
/// of the 2 DNs have one replica of each block.
/// 3. Add a DN to the cluster for later replication.
/// 4. Remove a DN that has data.
/// 5. Ask BlockManager to compute the replication work. This will assign
/// replication requests to the only DN that has data.
/// 6. Make sure the number of pending replication requests of that DN don't
/// exceed the limit.
/// </remarks>
/// <exception cref="System.Exception"/>
public virtual void TestNumberOfBlocksToBeReplicated()
{
// 1 min timeout
Configuration conf = new HdfsConfiguration();
conf.SetLong(DFSConfigKeys.DfsNamenodeMinBlockSizeKey, 0);
conf.SetLong(DFSConfigKeys.DfsBlockSizeKey, 1);
conf.SetInt(DFSConfigKeys.DfsBytesPerChecksumKey, 1);
// Large value to make sure the pending replication request can stay in
// DatanodeDescriptor.replicateBlocks before test timeout.
conf.SetInt(DFSConfigKeys.DfsHeartbeatIntervalKey, 100);
// Make sure BlockManager can pull all blocks from UnderReplicatedBlocks via
// chooseUnderReplicatedBlocks at once.
conf.SetInt(DFSConfigKeys.DfsNamenodeReplicationWorkMultiplierPerIteration, 5);
int NumOfBlocks = 10;
short RepFactor = 2;
string FileName = "/testFile";
Path FilePath = new Path(FileName);
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).NumDataNodes(RepFactor)
.Build();
try
{
// create a file with 10 blocks with a replication factor of 2
FileSystem fs = cluster.GetFileSystem();
DFSTestUtil.CreateFile(fs, FilePath, NumOfBlocks, RepFactor, 1L);
DFSTestUtil.WaitReplication(fs, FilePath, RepFactor);
cluster.StartDataNodes(conf, 1, true, null, null, null, null);
BlockManager bm = cluster.GetNamesystem().GetBlockManager();
ExtendedBlock b = DFSTestUtil.GetFirstBlock(fs, FilePath);
IEnumerator <DatanodeStorageInfo> storageInfos = bm.blocksMap.GetStorages(b.GetLocalBlock
()).GetEnumerator();
DatanodeDescriptor firstDn = storageInfos.Next().GetDatanodeDescriptor();
DatanodeDescriptor secondDn = storageInfos.Next().GetDatanodeDescriptor();
bm.GetDatanodeManager().RemoveDatanode(firstDn);
NUnit.Framework.Assert.AreEqual(NumOfBlocks, bm.GetUnderReplicatedNotMissingBlocks
());
bm.ComputeDatanodeWork();
NUnit.Framework.Assert.IsTrue("The number of blocks to be replicated should be less than "
+ "or equal to " + bm.replicationStreamsHardLimit, secondDn.GetNumberOfBlocksToBeReplicated
() <= bm.replicationStreamsHardLimit);
}
finally
{
cluster.Shutdown();
}
}