Logs and logging

Couchbase Server creates a number of different log files depending on the component of the system that produce the error, and the level and severity of the problem being reported.

Platform	Location
Linux	`/opt/couchbase/var/lib/couchbase/logs`
Windows	`C:\Program Files\Couchbase\Server\var\lib\couchbase\logs` Assumes default installation location
Mac OS X	`/Users/couchbase/Library/Application Support/Couchbase/var/lib/couchbase/logs`

Individual log files are automatically numbered, with the number suffix incremented for each new log, with a maximum of 20 files per log. Individual log file sizes are limited to 10MB by default.

File	Log Contents
`couchdb`	Errors relating to the couchdb subsystem that supports views, indexes and related REST API issues
`debug`	Debug level error messages related to the core server management subsystem, excluding information included in the `couchdb`, `xdcr` and `stats` logs.
`info`	Information level error messages related to the core server management subsystem, excluding information included in the `couchdb`, `xdcr` and `stats` logs.
`http_access.log`	The admin access log records server requests (including admin logins) coming through the REST or Couchbase web console. It is output in common log format and contains several important fields such as remote client IP, timestamp, GET/POST request and resource requested, HTTP status code, and so on.
`error`	Error level messages for all subsystems excluding `xdcr`.
`xcdr_error`	XDCR error messages.
`xdcr`	XDCR information messages.
`mapreduce_errors`	JavaScript and other view-processing errors are reported in this file.
`views`	Errors relating to the integration between the view system and the core server subsystem.
`stats`	Contains periodic reports of the core statistics.
`memcached.log`	Contains information relating to the core memcache component, including vBucket and replica and rebalance data streams requests.
`reports.log`	Contains only progress report and crash reports for the Erlang process.

Each log file group will also include a .idx and .siz file which holds meta information about the log file group. These files are automatically updated by the logging system.

Changing log file location

The default file log location is /opt/couchbase/var/lib/couchbase/logs, however, if you want to change the default log location to a different directory, change the log file configuration option.

Note

To implement a log file location change (from the default), you must be log in as either root or sudo and the Couchbase service must be restarted.

To change the log file configuration:

Log in as root or sudo and navigate to the directory where you installed Couchbase. For example: /opt/couchbase/etc/couchbase/static_config
Edit the static_config file and change the error_logger_mf_dir variable to a different directory. For example: {error_logger_mf_dir, "/home/user/cb/opt/couchbase/var/lib/couchbase/logs"}
Restart the Couchbase service. After restarting the Couchbase service, all subsequent logs will be in the new directory.

Changing logging levels

The default logging level for all log files are set to debug except for couchdb, which is set to info. If you want to change the default logging level, modify the logging level configuration options.

The configuration change can be performed in one of the following ways:

persistent
dynamic (on the fly, without restarting).

Changing logging levels to be persistent

Logging levels can be changed so that the changes are persistent, that is, the changes continue to be implemented should a Couchbase Server reboot occur.

Note: To implement logging level changes, the Couchbase service must be restarted.

To change logging levels to be persistent:

Log in as root or sudo and navigate to the directory where you installed Couchbase. For example: /opt/couchbase/etc/couchbase/static_config
Edit the static_config file and change the desired log component. For example, parameters with the loglevel_ prefix set the logging level.
Restart the Couchbase service.

After restarting the Couchbase service, logging levels for that component will be changed.

Changing logging levels dynamically

If logging levels are changed dynamically and if a Couchbase server reboot occurs, then the changed logging levels revert to the default.

To change logging levels dynamically, execute a curl POST command using the following syntax:


curl -X POST -u adminName:adminPassword
  HOST:PORT/diag/eval 
  –d ‘ale:set_loglevel(<log_component>,<logging_level>).’

Where:

Log_component: The default log level (except couchdb) is debug. For example, ns_server. The available loggers are ns_server, couchdb, user, Menelaus, ns_doctor, stats, rebalance, cluster, views, mapreduce_errors , xdcr and error_logger
Logging_level: The available log levels are debug, info, warning, and error.


curl -X POST -u Administrator:password 
	http://127.0.0.1:8091/diag/eval 
	-d 'ale:set_loglevel(ns_server,error).