@ganzuoni When restoring the snapshot it will copy all the files to the target directory, so it will read and rewrite every single file from the snapshot to the target directory and won't be skipped. So you have to be careful on which directory you are trying to restore and if you have concern if  you don't wants to restore on the existing file path, then restore on a different path. Also its not just the inode level operations, rather its complete copy operation with new inodes as the original file inodes still refers to the snapshot one. ... View more

Hello, Please try using the hdfs mover command. Refer: https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-hdfs/ArchivalStorage.html#Mover_-_A_New_Data_Migration_Tool ... View more

@allen_chu the possible reason could be the Datanode might be overwhelmed with multiple requests causing the network stall, if its specific this to this node then you may check the network level config  on this host, if not you may need to check at the overall cluster level load or any heavy write operations that is being pushed by the client to the HDFS. ... View more

Hello @rizalt  Do not try to delete anything on /hadoop/hdfs/data. From your query it seems you may have snapshots enabled which might be holding the blocks. Deleting the snapshots that belongs to /warehouse/tablespace/managed/hive may help to recover the space. You may check if the snapshot enabled for /warehourse or it child directory using below comamnd. $ hdfs lsSnapshottableDir If you find snapshot for this directory, you may delete it from Cloudera Manager using procedure specified in the below documentation. https://docs.cloudera.com/runtime/7.3.1/data-protection/topics/hdfs-deleting-snapshots-cm.html While deleting the snapshots start deleting with oldest to the newest.   ... View more

@JSSSS Looks like either you are running out of space in hdfs or the three DataNodes are too busy to acknowledge the request and causing the below exception. Please check if the HDFS is not reached its full capacity. org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicy: [ Datanode None is not chosen since required storage types are unavailable for storage type DISK. ... View more

@divyank The HDFS NameNode in safemode may happen due to its waiting for the DataNodes to send the block report. If that is not completed it may remain in the safemode. Ensure all the DataNodes started properly and no errors with it and connected to NameNode. You may review the NameNode logs and look for what its waiting for to exit safemode. Manually exiting the safemode may cause data loss of un reported blocks. If you have doubt, don't hesitate to contact Cloudera Support. ... View more

@irshan When you add balancer as a role in the HDFS cluster, it indeed will show as not started. So its an expected one. Coming to your main query, it could be possible that when you run the balancer, the balancer threshold could be with in the default percentage of 10, so it won't move the blocks. You may have to reduce the balance threshold and try again. ... View more

@Remme  Though the procedure you followed might have helped you, with a larger cluster with TBs of Data, this is not a viable option. In that case, would advise working with Cloudera Support. ... View more

@cc_yang It could be possible you may have enabled HDFS space quota to the directory and the directory may have reached to it hard limit, causing the file upload throws insufficient space message. Refer more about HDFS quota as below. https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsQuotaAdminGuide.html ... View more

Though one can do the manual intervention to fix the under replicated blocks, HDFS has matured a lot and  the NameNode will take care of fixing the under replicated blocks on its own. The drawback for doing the manual step is that it may add additional load to the NameNode Operations and may cause performance degradation with existing jobs. So if you plan to do manually you may do it at least business hours or over the weekend. ... View more