Each entry in the error log records the following properties (some are disabled by default and must be enabled):
Time stamp
Displays the date and time of the operation in the format DD/Month/YYYY:HH:MM:SS <offset from UTC time>.
Category
Specifies the message category that is loosely based on the server components.
Severity
Specifies the message severity of the event, which defines the importance of the message in terms of major errors that need to be quickly addressed. The default severity levels are fatal-error, notice, severe-error, and severe-warning.
Message ID
Specifies the numeric identifier of the message.
Message
Stores the error, warning, or informational message.
Note:

The following example displays an error log for the PingDataMetrics Server. The log is enabled by default and is accessible in the <server-root>/logs/errors file.

[21/Oct/2012:05:15:23.048 -0500] category=RUNTIME_INFORMATION severity=NOTICE
				msgID=20381715 msg="JVM Arguments: '-Xmx8g', '-Xms8g', '-XX:MaxNewSize=1g',
				'-XX:NewSize=1g', '-XX:+UseConcMarkSweepGC', '-XX:+CMSConcurrentMTEnabled',
				'-XX:+CMSParallelRemarkEnabled', '-XX:+CMSParallelSurvivorRemarkEnabled',
				'-XX:+CMSScavengeBeforeRemark', '-XX:RefDiscoveryPolicy=1',
				'-XX:ParallelCMSThreads=4', '-XX:CMSMaxAbortablePrecleanTime=3600000',
				'-XX:CMSInitiatingOccupancyFraction=80', '-XX:+UseParNewGC', '-XX:+UseMembar',
				'-XX:+UseBiasedLocking', '-XX:+UseLargePages', '-XX:+UseCompressedOops',
				'-XX:PermSize=128M', '-XX:+HeapDumpOnOutOfMemoryError',
				'-Dcom.unboundid.directory.server.scriptName=setup'"
				[21/Oct/2012:05:15:23.081 -0500] category=EXTENSIONS severity=NOTICE
				msgID=1880555611 msg="Administrative alert type=server-starting
				id=4178daee-ba3a-4be5-8e07-5ba17bf30b71
				class=com.unboundid.directory.server.core.MetricsEngine
				msg='The Metrics Server is starting'"
				[21/Oct/2012:05:15:23.585 -0500] category=CORE severity=NOTICE
				msgID=1879507338 msg="Starting group processing for backend api-users"
				[21/Oct/2012:05:15:23.586 -0500] category=CORE severity=NOTICE
				msgID=1879507339 msg="Completed group processing for backend api-users"
				[21/Oct/2012:05:15:23.586 -0500] category=EXTENSIONS severity=NOTICE
				msgID=1880555575 msg="'Group cache (2 static group(s) with 0 total
				memberships and 0 unique members, 0 virtual static group(s),
				1 dynamic group(s))' currently consumes 7968 bytes and can grow to a maximum
				of an unknown number of bytes"
				[21/Oct/2012:05:16:18.011 -0500] category=CORE severity=NOTICE
				msgID=458887 msg="The Metrics Server (Metrics Server 4.5.1.0
				build 20121021003738Z, R12799) has started successfully"
Note: Use dsconfig to modify the default File-Based Error Log, as in the following command:
$ bin/dsconfig set-log-publisher-prop \
					--publisher-name "File-Based Error Logger" \
					--set include-product-name:true --set include-instance-name:true \
					--set include-startup-id:true