Hi David How does your block replica count compare to the number of datanodes in your cluster?
Anyway...I found this in the online doc. You may want to use the NEVER policy. dfs.client.block.write.replace-datanode-on-failure.enable true If there is a datanode/network failure in the write pipeline, DFSClient will try to remove the failed datanode from the pipeline and then continue writing with the remaining datanodes. As a result, the number of datanodes in the pipeline is decreased. The feature is to add new datanodes to the pipeline. This is a site-wide property to enable/disable the feature. When the cluster size is extremely small, e.g. 3 nodes or less, cluster administrators may want to set the policy to NEVER in the default configuration file or disable this feature. Otherwise, users may experience an unusually high rate of pipeline failures since it is impossible to find new datanodes for replacement. See also dfs.client.block.write.replace-datanode-on-failure.policy dfs.client.block.write.replace-datanode-on-failure.policy DEFAULT This property is used only if the value of dfs.client.block.write.replace-datanode-on-failure.enable is true. ALWAYS: always add a new datanode when an existing datanode is removed. NEVER: never add a new datanode. DEFAULT: Let r be the replication number. Let n be the number of existing datanodes. Add a new datanode only if r is greater than or equal to 3 and either (1) floor(r/2) is greater than or equal to n; or (2) r is greater than n and the block is hflushed/appended. Allan On Oct 30, 2013 5:52 AM, "David Mankellow" <dmankel...@swiftserve.com> wrote: > Hi all, > > We are having difficulty writing any logs to a HDFS cluster of less than 3 > nodes. This has been since the update between cdh4.2 and 4.3 (4.4 is also > the same). Has anything changed that may make this occur and is there > anything that can be done to rectify the situation, so we can use a single > datanode once more? > > The error log contains errors about "lease recovery" and "Failed to add a > datanode". > > Here is an example stack trace: > > java.io.IOException: Failed to add a datanode. User may turn off this > feature by setting > dfs.client.block.write.**replace-datanode-on-failure.**policy > in configuration, where the current policy is DEFAULT. (Nodes: current=[ > 5.9.130.139:50010, 5.9.130.140:50010], original=[5.9.130.139:50010, > 5.9.130.140:50010]) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > findNewDatanode(**DFSOutputStream.java:816) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > addDatanode2ExistingPipeline(**DFSOutputStream.java:876) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > setupPipelineForAppendOrRecove**ry(DFSOutputStream.java:982) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > run(DFSOutputStream.java:493) > FSDataOutputStream#close error: > java.io.IOException: Failed to add a datanode. User may turn off this > feature by setting > dfs.client.block.write.**replace-datanode-on-failure.**policy > in configuration, where the current policy is DEFAULT. (Nodes: current=[ > 5.9.130.139:50010, 5.9.130.140:50010], original=[5.9.130.139:50010, > 5.9.130.140:50010]) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > findNewDatanode(**DFSOutputStream.java:816) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > addDatanode2ExistingPipeline(**DFSOutputStream.java:876) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > setupPipelineForAppendOrRecove**ry(DFSOutputStream.java:982) > at org.apache.hadoop.hdfs.**DFSOutputStream$DataStreamer.** > run(DFSOutputStream.java:493) > hdfsOpenFile(hdfs://storage1.**testing.swiftserve.com:9000/** > scribe/logs/test/log1.testing.**swiftserve.com/test-2013-10-**14_00000<http://storage1.testing.swiftserve.com:9000/scribe/logs/test/log1.testing.swiftserve.com/test-2013-10-14_00000>): > FileSystem#append((Lorg/**apache/hadoop/fs/Path;)Lorg/**apache/hadoop/fs/* > *FSDataOutputStream;) error: > org.apache.hadoop.ipc.**RemoteException(org.apache.**hadoop.hdfs.protocol. > **AlreadyBeingCreatedException): Failed to create file [/scribe/logs/test/ > log1.**testing.swiftserve.com/test-**2013-10-14_00000<http://log1.testing.swiftserve.com/test-2013-10-14_00000>] > for [DFSClient_NONMAPREDUCE_**1056562813_1] on client [5.9.130.136], > because this file is already being created by > [DFSClient_NONMAPREDUCE_**2007800327_1] > on [5.9.130.136] > at org.apache.hadoop.hdfs.server.**namenode.FSNamesystem.** > recoverLeaseInternal(**FSNamesystem.java:2062) > at org.apache.hadoop.hdfs.server.**namenode.FSNamesystem.** > startFileInternal(**FSNamesystem.java:1862) > at org.apache.hadoop.hdfs.server.**namenode.FSNamesystem.** > appendFileInt(FSNamesystem.**java:2105) > at org.apache.hadoop.hdfs.server.**namenode.FSNamesystem.** > appendFile(FSNamesystem.java:**2081) > at org.apache.hadoop.hdfs.server.**namenode.NameNodeRpcServer.** > append(NameNodeRpcServer.java:**434) > at org.apache.hadoop.hdfs.**protocolPB.** > ClientNamenodeProtocolServerSi**deTranslatorPB.append(** > ClientNamenodeProtocolServerSi**deTranslatorPB.java:224) > at org.apache.hadoop.hdfs.**protocol.proto.** > ClientNamenodeProtocolProtos$**ClientNamenodeProtocol$2.** > callBlockingMethod(**ClientNamenodeProtocolProtos.**java:44944) > at org.apache.hadoop.ipc.**ProtobufRpcEngine$Server$** > ProtoBufRpcInvoker.call(**ProtobufRpcEngine.java:453) > at org.apache.hadoop.ipc.RPC$**Server.call(RPC.java:1002) > at org.apache.hadoop.ipc.Server$**Handler$1.run(Server.java:**1701) > at org.apache.hadoop.ipc.Server$**Handler$1.run(Server.java:**1697) > at java.security.**AccessController.doPrivileged(**Native Method) > at javax.security.auth.Subject.**doAs(Subject.java:396) > at org.apache.hadoop.security.**UserGroupInformation.doAs(** > UserGroupInformation.java:**1408) > at org.apache.hadoop.ipc.Server$**Handler.run(Server.java:1695) > > at org.apache.hadoop.ipc.Client.**call(Client.java:1231) > at org.apache.hadoop.ipc.**ProtobufRpcEngine$Invoker.** > invoke(ProtobufRpcEngine.java:**202) > at $Proxy9.append(Unknown Source) > at sun.reflect.**GeneratedMethodAccessor6.**invoke(Unknown Source) > at sun.reflect.**DelegatingMethodAccessorImpl.**invoke(** > DelegatingMethodAccessorImpl.**java:25) > at java.lang.reflect.Method.**invoke(Method.java:597) > at org.apache.hadoop.io.retry.**RetryInvocationHandler.**invokeMethod( > **RetryInvocationHandler.java:**164) > at org.apache.hadoop.io.retry.**RetryInvocationHandler.invoke(** > RetryInvocationHandler.java:**83) > at $Proxy9.append(Unknown Source) > at org.apache.hadoop.hdfs.**protocolPB.** > ClientNamenodeProtocolTranslat**orPB.append(** > ClientNamenodeProtocolTranslat**orPB.java:210) > at org.apache.hadoop.hdfs.**DFSClient.callAppend(** > DFSClient.java:1352) > at org.apache.hadoop.hdfs.**DFSClient.append(DFSClient.**java:1391) > at org.apache.hadoop.hdfs.**DFSClient.append(DFSClient.**java:1379) > at org.apache.hadoop.hdfs.**DistributedFileSystem.append(** > DistributedFileSystem.java:**257) > at org.apache.hadoop.hdfs.**DistributedFileSystem.append(** > DistributedFileSystem.java:81) > at org.apache.hadoop.fs.**FileSystem.append(FileSystem.**java:1106) > > The exception suggests we have already set " dfs.client.block.write.** > replace-datanode-on-failure.**policy" to "NEVER" but hadoop ignores it. > > Any help would be appreciated. > > Thanks, > David Mankellow >
