IoTDB Log Overview

Log Description

Log paths: The default paths of IoTDB logs are /var/log/Bigdata/iotdb/iotdbserver (for storing run logs) and /var/log/Bigdata/audit/iotdb/iotdbserver (for storing audit logs).

Log archive rule: The automatic compression and archiving function of IoTDB is enabled. By default, when the size of a log file exceeds 20 MB (which is adjustable), the log file is automatically compressed. The naming rule of the compressed log file is as follows: <Original log file name>-<yyyymmdd>.ID.log.gz. A maximum of 10 latest compressed files are reserved. The number of compressed files and compression threshold can be configured.

**Table 1** IoTDB log list
Type	Name	Description
Run logs	log-all.log	IoTDB service log.
	log-error.log	IoTDB service error log.
	log-measure.log	IoTDB service monitoring log.
	log-query-debug.log	IoTDB query debug log.
	log-query-frequency.log	IoTDB query frequency log.
	log-sync.log	IoTDB synchronization log.
	log-slow-sql.log	IoTDB slow SQL log.
	server.out	Log that records IoTDB service startup exceptions.
	postinstall.log	IoTDB process startup log.
	prestart.log	Log that records IoTDB process startup exceptions.
	service-healthcheck.log	IoTDB database initialization log.
	start.log	IoTDBServer service startup log.
	stop.log	IoTDBServer service stop log.
	IoTDBServer-omm-<timestamp>-<pid>-gc.log.0.current	IoTDBServer service GC log.
Audit log	MRS 3.2.0: log_audit.log MRS 3.3.0 and later versions: log_datanode_audit.log	IoTDB audit log.

Log levels

Table 2 describes the log levels supported by IoTDB.

Levels of logs are ERROR, WARN, INFO, and DEBUG from the highest to the lowest priority. Run logs of equal or higher levels are recorded. The higher the specified log level, the fewer the logs recorded.

**Table 2** Log levels
Level	Description
ERROR	Logs of this level record error information about system running.
WARN	Logs of this level record exception information about the current event processing.
INFO	Logs of this level record normal running status information about the system and events.
DEBUG	Logs of this level record the system information and system debugging information.

To modify log levels, perform the following operations:

Go to the All Configurations page of the IoTDB service by referring to Modifying Cluster Service Configuration Parameters.
In the navigation tree on the left, select Log corresponding to the role to be modified.
Select a desired log level and save the configuration.

The IoTDB log level takes effect 60 seconds after being configured. You do not need to restart the service.

Log Formats

The following table lists the IoTDB log formats:

**Table 3** Log formats
Type	Format	Example
Run log	<yyyy-MM-dd HH:mm:ss,SSS> \| Log level \| [Thread name] \| Log information \| Log printing class (File:Line number)	2021-06-08 10:08:41,221 \| ERROR \| [main] \| Client failed to open SaslClientTransport to interact with a server during session initiation: \| org.apache.iotdb.rpc.sasl.TFastSaslTransport (TFastSaslTransport.java:257)
Audit log	<yyyy-MM-dd HH:mm:ss,SSS> \| Log level \| [Thread name] \| Log information \| Log printing class (File:Line number)	2021-06-08 11:03:49,365 \| INFO \| [ClusterClient-1] \| Session-1 is closing \| IoTDB_AUDIT_LOGGER (TSServiceImpl.java:326)