Using NFS

This section describes how to copy data from an HDFS cluster to a Data Fabric cluster using NFS.

About this task

If NFS is installed on the Data Fabric cluster, you can mount the Data Fabric cluster to the HDFS cluster and then copy files from one cluster to the other using hadoop distcp. If you do not have NFS installed and a mount point configured, see Accessing Data with NFS and Setting Up Data Fabric NFS.

To perform a copy using distcp via NFS, you need the following information:

  • <MapR NFS Server>: the IP address or hostname of the NFS server in the Data Fabric cluster
  • <maprfs_nfs_mount>: the NFS export mount point configured on the Data Fabric cluster; default is /mapr
  • <hdfs_nfs_mount>: the NFS mount point configured on the HDFS cluster
  • <NameNode>: the IP address or hostname of the NameNode in the HDFS cluster
  • <NameNode Port>: the port on the NameNode in the HDFS cluster
  • <HDFS path>: the path to the HDFS directory from which you plan to copy data
  • <MapR-FS path>: the path in the Data Fabric cluster to which you plan to copy HDFS data

To copy data from HDFS to file system using NFS, complete the following steps:

Procedure

  1. Issue the following command to mount the Data Fabric cluster to the HDFS NFS mount point: 
    mount <MapR NFS Server>:/<maprfs_nfs_mount> /<hdfs_nfs_mount>
    For example:
    mount 10.10.100.175:/mapr /hdfsmount
  2. Issue the following command to copy data from the HDFS cluster to the Data Fabric cluster: 
    hadoop distcp hdfs://<NameNode>:<NameNode Port>/<HDFS path> file:///<hdfs_nfs_mount>/<MapR-FS path>
    For example:
    hadoop distcp hdfs://nn1:8020/user/sara/file.txt file:///hdfsmount/user/sara
  3. Issue the following command from the Data Fabriccluster to verify that the file was copied to the Data Fabric cluster: 
    hadoop fs -ls /<MapR-FS path>
    For example:
    hadoop fs -ls /user/sara