hi, can someone suggest what could be the problem. i have big volume of missing blocks and namenode log error indicated that ipc max length is not enough, increased it, but that didn't help much, DNs before and after this increase still showing same that replica cache file doesn't exist, i don't see DNs are actually trying to connect to NN Setup is very small, 2 servers, 1 server used for NN and DN, second server is DN. Cloudera Express 6.3.1 Express used.   Configured Capacity: 3787349868544 (3.44 TB) Present Capacity: 3593183903744 (3.27 TB) DFS Remaining: 3235560472576 (2.94 TB) DFS Used: 357623431168 (333.06 GB) DFS Used%: 9.95% Replicated Blocks: Under replicated blocks: 0 Blocks with corrupt replicas: 0 Missing blocks: 7899994 Missing blocks (with replication factor 1): 405 Low redundancy blocks with highest priority to recover: 0 Pending deletion blocks: 0 Erasure Coded Block Groups: Low redundancy block groups: 0 Block groups with corrupt internal blocks: 0 Missing block groups: 0 Low redundancy blocks with highest priority to recover: 0 Pending deletion blocks: 0   Both DN1 & DN2 2024-03-24 10:16:51,876 INFO org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl: Adding replicas to map for block pool BP-1052250670-10.53.XXX-XX-XXXX981591679 on volume /opt/hadoop/dfs/dn... 2024-03-24 10:16:51,876 INFO org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.BlockPoolSlice: Replica Cache file: /opt/hadoop/dfs/dn/current/BP-1052250670-10.53.XXX-XX-XXXX981591679/current/replicas doesn't exist NameNode 2024-03-24 10:56:59,872 INFO org.apache.hadoop.hdfs.server.namenode.FSEditLog: Number of transactions: 28 Total time for transactions(ms): 15 Number of transactions batched in Syncs: 2 Number of syncs: 26 SyncTimes(ms): 64 2024-03-24 10:56:59,889 INFO org.apache.hadoop.ipc.Server: IPC Server handler 13 on 8020, call Call#23851 Retry#0 org.apache.hadoop.hdfs.protocol.ClientProtocol.addBlock from 10.53.235.25:39568 java.io.IOException: File /opt/logs/hdfs_canary_health/.canary_file_2024_03_24-10_56_59.f684be6f08559e9f could only be written to 0 of the 1 minReplication nodes. There are 0 datanode(s) running and 0 node(s) are excluded in this operation. at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:2102) at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.chooseTargetForNewBlock(FSDirWriteFileOp.java:294) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2673) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:872) at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:550) at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java) at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:523) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:991) at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:869) at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:815) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1875) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2675) ... View more