@Sriram Hadoop Nice to know it has answered your question. Could you Accept the answer I gave by Clicking on Accept button below, That would be a great help to Community users to find the solution quickly for these kinds of errors. ... View more

@Sriram Hadoop Hadoop Distributed File System was designed to hold and manage large amounts of data; therefore typical HDFS block sizes are significantly larger than the block sizes you would see for a traditional filesystem the block size is specified in hdfs-site.xml. The default block size in Hadoop 2.0 is 128mb, to change to 256MB edit the parameter, dfs.block.size to change to the desired block size eg 256 MB and you will need to restart all the stale services for the change to take effect. It's recommended to always use Ambari UI to make HDP/HDF changes Existing files' block size can't be changed, In order to change the existing files' block size, 'distcp' utility can be used. or Override the default block size with 265 MB hadoop fs -D dfs.blocksize=268435456 -copyFromLocal /tmp/test/payroll-april10.csv blksize/payroll-april10.csv Hope that helps ... View more

@Mudassar Hussain I am positive that command should and will work without fail if you have successfully created a snapshottable directory. Its a sub command of hdfs can you simply run hdfs a the hdfs user? $ hdfs Usage: hdfs [--config confdir] [--loglevel loglevel] COMMAND where COMMAND is one of: dfs run a filesystem command on the file systems supported in Hadoop. classpath prints the classpath namenode -format format the DFS filesystem secondarynamenode run the DFS secondary namenode namenode run the DFS namenode journalnode run the DFS journalnode ....... ........ snapshotDiff diff two snapshots of a directory or diff the current directory contents a snapshot lsSnapshottableDir list all snapshottable dirs owned by the current user Use -help to see options .... Most commands print help when invoked w/o parameters. Now once you have confirmed the above run as below # su - hdfs $ hdfs lsSnapshottableDir output .......................... drwxr-xr-x 0 mudassar hdfs 0 2018-03-15 10:38 1 65536 /user/mudassar/snapdemo That the directory I created to reproduce your issues on my cluster. ... View more

@Mudassar Hussain No worries I was worried you got stuck and didn't revert the HCC is full of solutions so, don't hesitate to update the thread if you encounter any problems but if the solution provided resolves your issue then that's great what you need to do is accept and close the thread Cheers ... View more

@Mudassar Hussain You haven't given your feedback on the method and solution I provided, you should understand that members go a long way to help out and feedback as to whether the solution resolved your problem is appreciated and in that case you accept the answer to reward the user and close the thread,so that others with a similar problem could use it as a SOLUTION. ... View more

@Mudassar Hussain Any updates ? ... View more

In this examples I am using a Cloudera virtual box but it the same command on HDP. I didn't create a local user mudassar but used hdfs and the hdfs directory ################################# # Whoami ################################# # id uid=0(root) gid=0(root) groups=0(root) ################################# # Switched to hdfs user ################################# # su - hdfs ################################# # Changed directory to tmp to create test files ################################# $ cd /tmp ################################# # Created first file ################################# $ echo "This is the first text file for mudassar to test snapshot" > text1.txt ################################# # Created second file ################################# $ echo "Apache Kafka comes with a pluggable authorizer known as Kafka Authorization Command Line (ACL) Interface, which is used for defining users and allowing or denying them to access its various APIs. The default behavior is that only a superuser is allowed to access all the resources of the Kafka cluster, and no other user can access those resources if no proper ACL is defined for those users. The general format in which Kafka ACL is defined is as follows" > text2.txt ################# # Here is output ################ $ ls -lrt -rw-rw-r-- 1 hdfs hdfs 58 Mar 8 00:34 text1.txt -rw-rw-r-- 1 cloudera hdfs 456 Mar 8 00:37 text2.txt ################################# # Above I changed the owner of text2.txt to cloudera as root user in the local filesystem ################################# #chown cloudera:hdfs /tmp/text2.txt ################################ # First create a target directory in hdfs ################################ hdfs dfs -mkdir /user/mudassar ################################ # create a snapshottable directory ################################# hdfs dfsadmin -allowSnapshot /user/mudassar output: Allowing snaphot on /user/mudassar succeeded ################################# # Check the snapshottable dir in HDFS ################################# hdfs lsSnapshottableDir Output drwxr-xr-x 0 hdfs supergroup 0 2018-03-08 00:54 0 65536 /user/mudassar ################################# # copy a file from local to the HDFS snapshotable directory ################################# hdfs dfs -put /tmp/text1.txt /user/mudassar ################################# # Validate the files was copied ################################# hdfs dfs -ls /user/mudassar Found 1 items -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt ################################# # create snapshot ################################# hdfs dfs -createSnapshot /user/mudassar Output Created snapshot /user/mudassar/.snapshot/s20180308-005619.181 ################################# # Check to see the snapshot ################################# hdfs dfs -ls /user/mudassar/.snapshot Output Found 1 items drwxr-xr-x - hdfs supergroup 0 2018-03-08 00:56 /user/mudassar/.snapshot/s20180308-005619.181 ################################# # copy another file to the directory ################################# hdfs dfs -put /tmp/text2.txt /user/mudassar ################################# # Check the files exit in /user/mudassar notice the timestamp,permissions etc ################################# hdfs dfs -ls /user/mudassar output Found 2 items -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt -rw-r--r-- 1 hdfs supergroup 456 2018-03-08 00:58 /user/mudassar/text2.txt ################################# # Changed ownership of one of the files ################################# hdfs dfs -chown cloudera:supergroup /user/mudassar/text2.txt ################################# #Create second snapshot ################################# hdfs dfs -createSnapshot /user/mudassar ################################# # checked the directory notice now we have 2 snapshots one contains ONLY texte1.txt and the other contains both files ################################# $ hdfs dfs -ls /user/mudassar/.snapshot Output Found 2 items drwxr-xr-x - hdfs supergroup 0 2018-03-08 00:56 /user/mudassar/.snapshot/s20180308-005619.181 drwxr-xr-x - hdfs supergroup 0 2018-03-08 01:01 /user/mudassar/.snapshot/s20180308-010152.924 ################################# # Simulate accidental deletion of the files ################################# hdfs dfs -rm /user/mudassar/* output 18/03/08 01:06:26 INFO fs.TrashPolicyDefault: Moved: 'hdfs://quickstart.cloudera:8020/user/mudassar/text1.txt' to trash at: hdfs://quickstart.cloudera:8020/user/hdfs/.Trash/Current/user/mudassar/text1.txt 18/03/08 01:06:26 INFO fs.TrashPolicyDefault: Moved: 'hdfs://quickstart.cloudera:8020/user/mudassar/text2.txt' to trash at: hdfs://quickstart.cloudera:8020/user/hdfs/.Trash/Current/user/mudassar/text2.txt ################################# # Validate the files were deleted ################################# hdfs dfs -ls /user/mudassar Will return nothing but the directory exist, run hdfs dfs -ls /user/ ################################# # check the contents of the latest snapshot xxxxx.924 see above ################################# hdfs dfs -ls -R /user/mudassar/.snapshot/s20180308-010152.924 output -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/.snapshot/s20180308-010152.924/text1.txt -rw-r--r-- 1 cloudera supergroup 456 2018-03-08 00:58 /user/mudassar/.snapshot/s20180308-010152.924/text2.txt ################################# # Recover the 2 files from snapshot using -ptopax option ################################# hdfs dfs -cp -ptopax /user/mudassar/.snapshot/s20180308-010152.924/* /user/mudassar/ ################################# # Validate the files were restored with original timestamps, ownership, permission, ACLs and XAttrs. ################################# hdfs dfs -ls /user/mudassar output -rw-r--r-- 1 hdfs supergroup 58 2018-03-08 00:55 /user/mudassar/text1.txt -rw-r--r-- 1 cloudera supergroup 456 2018-03-08 00:58 /user/mudassar/text2.txt There you are recovered the 2 files delete accidentally ,please let me know if that worked out for you ... 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1. To add on to Artem's idea. Disable IPv6 Temporarily 'echo 1 > /proc/sys/net/ipv6/conf/<interface-name>/disable_ipv6' eg 'echo 1 > /proc/sys/net/ipv6/conf/eth0/disable_ipv6' Disable IPv6 Permanently across reboots Edit the /etc/sysctl.conf and the following lines. # to disable IPv6 on all interfaces system wide net.ipv6.conf.all.disable_ipv6 = 1 # to disable IPv6 on a specific interface (e.g., eth0, lo) net.ipv6.conf.lo.disable_ipv6 = 1 net.ipv6.conf.eth0.disable_ipv6 = 1 2. Check the NTP server configuration or just restart NTP on both servers ... View more