[ https://issues.apache.org/jira/browse/HDFS-16182?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Max Xie updated HDFS-16182: ---------------------------- Attachment: (was: HDFS-16182.patch) > numOfReplicas is given the wrong value in > BlockPlacementPolicyDefault$chooseTarget can cause DataStreamer to fail with > Heterogeneous Storage > ----------------------------------------------------------------------------------------------------------------------------------------------- > > Key: HDFS-16182 > URL: https://issues.apache.org/jira/browse/HDFS-16182 > Project: Hadoop HDFS > Issue Type: Bug > Components: namanode > Affects Versions: 3.4.0 > Reporter: Max Xie > Assignee: Max Xie > Priority: Major > Labels: pull-request-available > Time Spent: 10m > Remaining Estimate: 0h > > In our hdfs cluster, we use heterogeneous storage to store data in SSD for a > better performance. Sometimes hdfs client transfer data in pipline, it will > throw IOException and exit. Exception logs are below: > ``` > java.io.IOException: Failed to replace a bad datanode on the existing > pipeline due to no more good datanodes being available to try. (Nodes: > current=[DatanodeInfoWithStorage[dn01_ip:5004,DS-ef7882e0-427d-4c1e-b9ba-a929fac44fb4,DISK], > > DatanodeInfoWithStorage[dn02_ip:5004,DS-3871282a-ad45-4332-866a-f000f9361ecb,DISK], > > DatanodeInfoWithStorage[dn03_ip:5004,DS-a388c067-76a4-4014-a16c-ccc49c8da77b,SSD], > > DatanodeInfoWithStorage[dn04_ip:5004,DS-b81da262-0dd9-4567-a498-c516fab84fe0,SSD], > > DatanodeInfoWithStorage[dn05_ip:5004,DS-34e3af2e-da80-46ac-938c-6a3218a646b9,SSD]], > > original=[DatanodeInfoWithStorage[dn01_ip:5004,DS-ef7882e0-427d-4c1e-b9ba-a929fac44fb4,DISK], > > DatanodeInfoWithStorage[dn02_ip:5004,DS-3871282a-ad45-4332-866a-f000f9361ecb,DISK]]). > The current failed datanode replacement policy is DEFAULT, and a client may > configure this via > 'dfs.client.block.write.replace-datanode-on-failure.policy' in its > configuration. > ``` > After search it, I found when existing pipline need replace new dn to > transfer data, the client will get one additional dn from namenode and check > that the number of dn is the original number + 1. > ``` > ## DataStreamer$findNewDatanode > if (nodes.length != original.length + 1) { > throw new IOException( > "Failed to replace a bad datanode on the existing pipeline " > + "due to no more good datanodes being available to try. " > + "(Nodes: current=" + Arrays.asList(nodes) > + ", original=" + Arrays.asList(original) + "). " > + "The current failed datanode replacement policy is " > + dfsClient.dtpReplaceDatanodeOnFailure > + ", and a client may configure this via '" > + BlockWrite.ReplaceDatanodeOnFailure.POLICY_KEY > + "' in its configuration."); > } > ``` > The root cause is that Namenode$getAdditionalDatanode returns multi datanodes > , not one in DataStreamer.addDatanode2ExistingPipeline. > > Maybe we can fix it in BlockPlacementPolicyDefault$chooseTarget. I think > numOfReplicas should not be assigned by requiredStorageTypes. > > > > > > -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org