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.
  - maprcli and REST API Syntax
    This section provides information about the MapR command API. Most commands can be run on the command-line interface (CLI), or by making REST requests programmatically or in a browser.
  - Utilities
    This section contains information about various scripts and utilities.
    - configure.sh
    - configure-crosscluster.sh
    - cldbguts
    - disksetup
    - expandaudit
    - fcdebug
    - fsck
    - gfsck
      Describes how you can use the gfsck command, under the supervision of MapR Support or Engineering, to perform consistency checks and appropriate repairs on a volume, or a volume snapshot.
    - mapr-support-collect.sh
    - mapr-support-dump.sh
    - maprlogin
    - mrconfig
    - mrdirectorystats
    - mrfscmd
    - pullcentralconfig
    - stubfuse
  - Configuration Files
    This section contains reference information about various configuration files.
  - Alarms Reference
    The pages in this section provide details about all of the types of alarms.
  - MapR Environment
    This section provides information associated with the MapR environment.
- Troubleshooting Cluster Administration
- Best Practices for Backing Up MapR Information

fcdebug

The fcdebug utility can be used to dynamically set the loglevel to debug a library.

The core-site.xml file can be modified to set the loglevel of all modules using the fs.mapr.trace property. However, FUSE must be restarted for the change to take effect. The fcdebug utility allows you to debug a specific library (at runtime) without restarting FUSE.

NOTE: You may have to run this command once per library (to debug).

Syntax

/opt/mapr/server/tools/fcdebug [-i] -s <shmid> [-m <module>] [-l <level>]

Parameters

Parameter	Description
`-i`	Lists the current debug level of all modules.
`-l`	Specifies the log level. Value can be one of the following: FATAL, ERROR, WARN, INFO, DEBUG. NOTE: If this is not specified, the default level is applied for the module.
`-m`	Refers to the module. The list of modules can be retrieved by running `fcdebug -i -s <shmid>` command. NOTE: If this is not specified, the loglevel is set on all modules.
`-s`	Specifies the process ID of the fileclient or FUSE-based POSIX client. If the process ID is not available, specify the ID of the shared memory segment, which has the size of 1234 bytes.

Examples

The following command retrieves the list of modules:

/opt/mapr/server/tools/fcdebug -i -s 196614

NOTE: You can run this command after dynamically setting the loglevel to also verify the setting.

The following command dynamically sets the log level to DEBUG on the given module:

/opt/mapr/server/tools/fcdebug -s 196614 -m FuseOps -l DEBUG

NOTE: It may take up to a minute for the changes to take effect.

The following command sets loglevel to DEBUG on all the modules:

/opt/mapr/server/tools/fcdebug -s 196614 -l DEBUG

The following command resets the log level to the default value on all the modules:

/opt/mapr/server/tools/fcdebug -s 196614