Database logs

EventStoreDB logs its internal operations to the console (stdout) and to log files. The default location of the log files and the way to change it is described below.

There are a few options to change the way how EventStoreDB produces logs and how detailed the logs should be.

Warning

The EventStoreDB logs may contain sensitive information such as stream names, user names, and projection definitions.

Log format

EventStoreDB uses the structured logging in JSON format that is more machine-friendly and can be ingested by vendor-specific tools like Logstash or Datadog agent.

Here is how the structured log looks like:

{
  "PID": "6940",
  "ThreadID": "23",
  "Date": "2020-06-16T16:14:02.052976Z",
  "Level": "Debug",
  "Logger": "ProjectionManager",
  "Message": "PROJECTIONS: Starting Projections Manager. (Node State : {state})",
  "EventProperties": {
    "state": "Master"
  }
}
{
  "PID": "6940",
  "ThreadID": "15",
  "Date": "2020-06-16T16:14:02.052976Z",
  "Level": "Info",
  "Logger": "ClusterVNodeController",
  "Message": "========== [{internalHttp}] Sub System '{subSystemName}' initialized.",
  "EventProperties": {
    "internalHttp": "127.0.0.1:2112",
    "subSystemName": "Projections"
  }
}
{
  "PID": "6940",
  "ThreadID": "23",
  "Date": "2020-06-16T16:14:02.052976Z",
  "Level": "Debug",
  "Logger": "MultiStreamMessageWriter",
  "Message": "PROJECTIONS: Resetting Worker Writer",
  "EventProperties": {}
}
{
  "PID": "6940",
  "ThreadID": "23",
  "Date": "2020-06-16T16:14:02.055000Z",
  "Level": "Debug",
  "Logger": "ProjectionCoreCoordinator",
  "Message": "PROJECTIONS: SubComponent Started: {subComponent}",
  "EventProperties": {
    "subComponent": "EventReaderCoreService"
  }
}

This format is aligned with Serilog Compact JSON format.

Logs location

Log files are located in /var/log/eventstore for Linux and macOS, and in the logs subdirectory of the EventStoreDB installation directory on Windows. You can change the log files location using the Log configuration option.

Tips

Moving logs to a separate storage might improve the database performance if you keep the default verbose log level.

Format	Syntax
Command line	--log
YAML	Log
Environment variable	EVENTSTORE_LOG

For example, adding this line to the eventstore.conf file will force writing logs to the /tmp/eventstore/logs directory:

Log: /tmp/eventstore/logs

Log level

You can change the level using the LogLevel setting:

Format	Syntax
Command line	--log-level
YAML	LogLevel
Environment variable	EVENTSTORE_LOG_LEVEL

Acceptable values are: Default, Verbose, Debug, Information, Warning, Error, and Fatal.

Logging options

You can tune the EventStoreDB logging further by using the logging options described below.

Log configuration file

Specifies the location of the file which configures the logging levels of various components.

Format	Syntax
Command line	--log-config
YAML	LogConfig
Environment variable	EVENTSTORE_LOG_CONFIG

By default, the application directory (and /etc/eventstore on Linux and Mac) are checked. You may specify a full path.

HTTP requests logging

EventStoreDB can also log all the incoming HTTP requests, like many HTTP servers do. Requests are logged before being processed, so unsuccessful requests are logged too.

Use one of the following ways to enable the HTTP requests logging:

Format	Syntax
Command line	--log-http-requests
YAML	LogHttpRequests
Environment variable	EVENTSTORE_LOG_HTTP_REQUESTS

Default: false, logging HTTP requests is disabled by default.

Log failed authentication

For security monitoring, you can enable logging failed authentication attempts by setting LogFailedAuthenticationAttempts setting to true.

Format	Syntax
Command line	--log-failed-authentication-attempts
YAML	LogFailedAuthenticationAttempts
Environment variable	EVENTSTORE_LOG_FAILED_AUTHENTICATION_ATTEMPTS

Default: false

Log console format

The format of the console logger. Use Json for structured log output.

Format	Syntax
Command line	--log-console-format
YAML	LogConsoleFormat
Environment variable	EVENTSTORE_LOG_CONSOLE_FORMAT

Acceptable values are: Plain, Json

Default: Plain

Log file size

The maximum size of each log file, in bytes.

Format	Syntax
Command line	--log-file-size
YAML	LogFileSize
Environment variable	EVENTSTORE_LOG_FILE_SIZE

Default: 1GB

Log file interval

How often to rotate logs.

Format	Syntax
Command line	--log-file-interval
YAML	LogFileInterval
Environment variable	EVENTSTORE_LOG_FILE_INTERVAL

Acceptable values are: Minute, Hour, Day, Week, Month, Year

Default: Day

Log file retention count

How many log files to hold on to.

Format	Syntax
Command line	--log-file-retention-count
YAML	LogFileRetentionCount
Environment variable	EVENTSTORE_LOG_RETENTION_COUNT

Default: 31

Disable log file

You can completely disable logging to a file by changing the DisableLogFile option.

Format	Syntax
Command line	--disable-log-file
YAML	DisableLogFile
Environment variable	EVENTSTORE_DISABLE_LOG_FILE

Default: false