--Trash
sudo vi /etc/hadoop/conf/core-site.xml
<property>
<name>fs.trash.interval</name>
<value>60</value>
</property>
<property>
<name>fs.trash.checkpoint.interval</name>
<value>45</value>
</property>
sudo service hadoop-hdfs-namenode restart
--Skip Trash
hadoop fs -rm -skipTrash delete-file2
--Snapshots
hadoop fs -mkdir important-files
hadoop fs -copyFromLocal file1 file2 important-files
hdfs dfs -createSnapshot /user/ubuntu/important-files
--Require admin rights
hdfs dfsadmin -allowSnapshot /user/ubuntu/important-files
--Snapshot creation - demonstrate file add & deletes
hdfs dfs -createSnapshot /user/ubuntu/important-files snapshot1
hadoop fs -ls /user/ubuntu/important-files/.snapshot
hadoop fs -ls /user/ubuntu/important-files/.snapshot/snapshot1
hadoop fs -rm /user/ubuntu/important-files/.snapshot/snapshot1/file1
hadoop fs -rm /user/ubuntu/important-files/file2
hadoop fs -copyFromLocal file3 /user/ubuntu/important-files
hdfs dfs -createSnapshot /user/ubuntu/important-files snapshot2
hadoop fs -ls /user/ubuntu/important-files/.snapshot/snapshot2
hadoop fs -ls /user/ubuntu/important-files
hadoop fs -ls /user/ubuntu/important-files/.snapshot/snapshot1
hadoop fs -cat /user/ubuntu/important-files/.snapshot/snapshot1/file2
hdfs snapshotDiff /user/ubuntu/important-files snapshot2 snapshot1
--Demonstrate file modifications
cat append-file
hadoop fs -appendToFile append-file /user/ubuntu/important-files/file1
hadoop fs -cat /user/ubuntu/important-files/file1
hdfs dfs -createSnapshot /user/ubuntu/important-files snapshot3
hadoop fs -ls /user/ubuntu/important-files/.snapshot/snapshot3
hdfs snapshotDiff /user/ubuntu/important-files snapshot3 snapshot2
hadoop fs -cat /user/ubuntu/important-files/.snapshot/snapshot2/file1
hadoop fs -cat /user/ubuntu/important-files/.snapshot/snapshot3/file1
hadoop fs -cat /user/ubuntu/important-files/file1
--Delete snapshots
hdfs dfs -deleteSnapshot /user/ubuntu/important-files snapshot1
hadoop fs -ls /user/ubuntu/important-files/.snapshot
--Require admin rights
hdfs dfsadmin -disallowSnapshot /user/ubuntu/important-files
