6.0 Administration
This section describes how to manage the nodes and services that make up a cluster.
- Administering Users and Clusters
- Administering Nodes
- Administering Volumes
  This section provide information about how to organize and manage data using volumes, a unique feature of MapR clusters.
- Administering Files and Directories
- Administering Tables
  Administration of the MapR-DB is done primarily via the command line (maprcli) or with the MapR Control System (MCS). Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. MapR-DB administration is associated with tables, columns and column families, and table regions.
- Administering Streams
- Administering MapR Gateways
  A MapR gateway mediates one-way communication between a source MapR cluster and a destination cluster. You can replicate MapR-DB tables (binary and JSON) and MapR-ES streams. MapR gateways also apply updates from JSON tables to their secondary indexes and propagate Change Data Capture (CDC) logs.
- Administering Services
- Monitoring the Cluster
  This section describes how to monitor the health and performance of a MapR cluster.
- Configuring Security
  Describes how to configure MapR security and manage secure clusters.
- Managing Secure Clusters
  Provides procedures that will enable you to use MapR clusters securely.
- Administering the MapR Data Access Gateway
  The MapR Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the MapR cluster. This section describes considerations when upgrading the service, how to modify configuration settings, and how to administer and manage the service.
- Planning for High Availability
- Administrator's Reference
  This section contains in-depth reference information for the administrator.
- Troubleshooting Cluster Administration
- Best Practices for Backing Up MapR Information

Accessing Data with NFSv3

Unlike other Hadoop distributions that only allow cluster data import or import as a batch operation, MapR lets you mount the cluster itself via NFS so that your applications can read and write data directly. MapR allows direct file modification and multiple concurrent reads and writes via POSIX semantics. With an NFS-mounted cluster, you can read and write data directly with standard tools, applications, and scripts. For example, you could run a MapReduce application that outputs to a CSV file, then import the CSV file directly into SQL via NFS.

MapR exports each cluster as the directory /mapr/<cluster name> (for example, /mapr/my.cluster.com). If you create a mount point with the local path /mapr, then Hadoop FS paths and NFS paths to the cluster will be the same. This makes it easy to work on the same files via NFS and Hadoop. In a multi-cluster setting, the clusters share a single namespace, and you can see them all by mounting the top-level /mapr directory.

WARNING: MapR uses version 3 of the NFS protocol. NFS version 4 bypasses the port mapper and attempts to connect to the default port only. If you are running NFS on a non-standard port, mounts from NFS version 4 clients time out. Use the -o nfsvers=3 option to specify NFS version 3.

You can mount the cluster on a Linux, Mac, or Windows client. Before you begin, make sure you know the hostname and directory of the NFS share you plan to mount.