How do you retrieve the replication factor info in Hdfs files?
I have set the replication factor for my file as follows:
hadoop fs -D dfs.replication=5 -copyFromLocal file.txt /user/xxxx
NameNode restarts, it makes sure under-replicated blocks are replicated.
Hence the replication info for the file is stored (possibly in
nameNode). How can I get that information?
Try to use command
hadoop fs -stat %r /path/to/file, it should print the replication factor.
How to configure replication factor and block size for HDFS?, Which HDFS command modifies the replication factor of a file? The replication factor is a property that can be set in the HDFS configuration file that will allow you to adjust the global replication factor for the entire cluster. For each block stored in HDFS, there will be n – 1 duplicated blocks distributed across the cluster.
You can run following command to get replication factor,
hadoop fs -ls /user/xxxx
The second column in the output signify replication factor for the file and for the folder it shows
-, as shown in below pic.
What is the replication factor in HDFS, and how can we set it?, method 2: Get the replication factor using the stat hdfs command tool. Using the above file as an example: $ hdfs dfs -stat %r /usr/GroupStorage/ A related question: how to find the replication factors of files in a HDFS cluster? method 1 : You can use the HDFS command line to ls the file. The second column of the output will show the replication factor of the file.
Apart from Alexey Shestakov's answer, which works perfectly and does exactly what you ask, other ways, mostly found here, include:
hadoop dfs -ls /parent/path
which shows the replication factors of all the
/parent/path contents on the second column.
Through Java, you can get this information by using:
You can also see the replication factors of files by using:
hadoop fsck /filename -files -blocks -racks
Finally, from the web UI of the namenode, I believe that this information is also available (didn't check that).
Hadoop HDFS Data Read and Write Operations, I have set the replication factor for my file as follows: hadoop fs -D dfs.replication=5 -copyFromLocal file.txt /user/xxxx When a NameNode restarts, it makes sure You can run hdfs fsck to list all files with their replication counts and grep those with replication factor 1. Run the following command as a HDFS superuser: $ hdfs fsck / -files -blocks -racks | grep repl=1
We can use following commands to check replication of the file.
hdfs dfs -ls /user/cloudera/input.txt
hdfs dfs -stat %r /user/cloudera/input.txt
Why replication is done in hdfs Hadoop, The replication factor is 3 by default (there would be one original block and How does a file get stored on HDFS? This information is stored in NameNode. Replication factor is the number of replication we are creating for a particular block as to avoid any fault in system if any data block or data gets deleted or lost. The default replication factor of HDFS is 3 but we can make changes according to user requirement.
How to check the replication factor of a file in HDFS?, File Deletes and Undeletes; Decrease Replication Factor HDFS provides high throughput access to application data and is suitable for applications that have large data sets. HDFS relaxes file. This information is stored by the NameNode. Column 2 shows the replication factor for files. (The concept of replication doesn’t apply to directories.) The blocks that make up a file in HDFS are replicated to ensure fault tolerance. The replication factor, or the number of replicas that are kept for a specific file, is configurable. You can specify the replication factor when the file is created or later, via your application.
How do you retrieve the replication factor info in Hdfs files?, HDFS supports a traditional hierarchical file organization. A user or an or rename a file. HDFS supports user quotas and access permissions. HDFS by HDFS. The number of copies of a file is called the replication factor of that file. This information is stored by the NameNode. Till now you should have got some idea of Hadoop and HDFS. In tutorial 1 and tutorial 2 we talked about the overview of Hadoop and HDFS. Lets get a bit more technical now and see how Read Operations are performed in HDFS but before that we will see what is replica of data or replication in Hadoop and how namenode manages it.
HDFS Architecture Guide - Apache Hadoop, You can change the replication factor for a file anytime with the hdfs dfs hdfs dfs –setrep option, the NameNode sends the information about The replication factor can be specified at the time of creation of the file and can be changed later. Files in HDFS are write-once and have strictly one writer at any time. The replication factor is a property that can be set in the HDFS configuration file. It also allows you to adjust the global replication factor for the entire cluster.