HPE Ezmeral Data Fabric 6.1.x is In Maintenance and transitions to "End of Maintenance" in June 2024. Please see the latest documentation.

About MapR 6.1
This site contains the main documentation for Version 6.1 of the MapR Converged Data Platform, including installation, configuration, administration, and reference information.
6.1 Installation
This section contains information about installing and upgrading MapR software. It also contains information about how to migrate data and applications from an Apache Hadoop cluster to a MapR cluster.
6.1 MapR Data Platform
MapR Data Platform is the industry-leading data platform for AI and analytics that solves enterprise business needs.
6.1 Administration
This section describes how to manage the nodes and services that make up a cluster.
- Administering Users and Clusters
  Lists topics that help manage a MapR cluster.
- Administering Nodes
  Provides a synopsis of managing nodes in a cluster.
- 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
  - Using Global File System Checking
    Describes how to use the gfsck command to check and repair file system errors.
  - Setting MapR File System Permissions
  - Managing File and Directory ACEs
    Describes the implications of setting access control expressions on files and directories.
  - Managing Chunk Size
    Describes the considerations for managing the chunk size for map tasks.
  - Managing Compression
    Lists the advantages of using compression.
  - Managing Hard Links
    Explains what hard links are, and their limitations.
  - Managing Extended Attributes
    Describes what extended attributes are, and the POSIX permissions that you need to manage them.
  - Managing Core Files
    Describes how to set the location for core files.
  - Migrating Files from the Edge Cluster to AWS S3
    Describes how new or changed files are automatically uploaded to AWS S3 by the File Migration service.
  - Managing Tiered Files from the Command-line
- Administering Tables
  Administration of the MapR Database is done primarily via the command line (maprcli) or with the Managed Control System (MCS). Regardless of whether the MapR Database table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. MapR Database 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 Database tables (binary and JSON) and MapR Event Store For Apache Kafka 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 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
  Lists the common errors and their solutions.
- Best Practices for Backing Up MapR Information
  Lists the best practices and performance considerations to follow when backing up MapR information.
6.1 Development
This section contains information related to application development for Ezmeral ecosystem components and MapR Data Platform products, including the file system, Database (Key-Value and JSON), and Event Streams.
Other Docs
This section contains release-independent information, including: MapR Installer documentation, Ecosystem release notes, interoperability matrices, security vulnerabilities, and links to other MapR version documentation.
Glossary
Definitions for commonly used terms in MapR Converged Data Platform environments.

Managing Core Files

Describes how to set the location for core files.

The Linux core_pattern file (in /proc/sys/kernel/core_pattern) can be used to specify the location for storing core files. If any process launched by MapR crashes, the core files are created in the directory specified by the core_pattern file. A valid location in the core_pattern file is a full path to the directory you want to use. For example:

/tmp/dir1/cores/%e.core.%p.%h

TIP For details about the standard Linux % specifiers that you can use to name core files, see the core man page.

If the core_pattern file is empty, if the file does not contain a full path, or if it uses the "|" redirection feature, by default, MapR sets the location for core files (in the event of a core dump on a node) to /opt/cores directory when:

The configure.sh utility is run.
The Warden init script is run.
The MapR File System init script is run by Warden.

The default directory (/opt/cores) is also used if the core_pattern file contains the default MapR value for core files.

For MapR software, the directory being used to store core files should not be used for other purposes and should be empty. The cores directory cannot be the home directory, as it can cause problems during SSH access. The hoststats service monitors the directory specified in the core_pattern file and raises the node-level alarm if the directory contains any entry other than "." and "..". When Warden is started, sticky bit is set on the cores directory.