Managing Audit Logs for File System and Table Operations

There are three parameters that you can use to manage audit logs for file system and table operations:
  • -maxSize
  • -retention
  • -coalesce

You can set the first two parameters with the maprcli audit data command. You can set the third parameter with the maprcli volume audit command.

Effects of the -maxSize parameter

When you enable auditing with the audit datamaprcli audit data command, you can use the -maxSize parameter to specify the size at which an alarm is raised concerning the size of the audit volume. The alarm is displayed on the dashboard in the Control System and in the output of the alarm listmaprcli alarm list command. This alarm simply means that the threshold size has been reached. Audited operations are still logged to the audit volume in question.

There are three actions that you can take:

  • If you decide that you want to be notified when the audit volume reaches a smaller or larger size, you can change the threshold by running the maprcli audit data command and changing the value of the -maxSize parameter.
  • If you want to try preventing audit log files from growing as quickly as they are, you can change the number of identical operations that are logged within a number of minutes. Run the maprcli audit data command and increase the value of the -coalesce parameter. This parameter is described subsequently.
  • If you are concerned about longer-term space requirements for storing audit log files, you can change the number of days to keep old log files before they are deleted. Run the maprcli audit data command and decrease the value of the -retention parameter. This parameter is also described below.

Effects of the -retention parameter

When you enable auditing with the maprcli audit data command, you can use the -retention parameter to specify how many days to keep old log files.

Audit logs are rotated every night at midnight UTC time . The saved audit logs are kept until the retention period expires.

For example, suppose the retention period is 30 days. The node 192.168.10.15 in the volume /myVolume contains 30 days of saved log files for file-system operations and the current date is March 30, 2016. The directory /var/mapr/local/102.168.10.15/audit/ contains these log files:

FSAudit.log.json-30-03-2016-001

FSAudit.log.json-29-03-2016-001

FSAudit.log.json-28-03-2016-001

…

FSAudit.log.json-01-03-2016-001

NOTE
If MFS is restarted on the same day, audit logs gets rotated, and new files with convention -002, -003, and so on are created with each restart.

If there is no more disk space for new entries in audit logs, audit logging stops.

If the size of the audit log volume exceeds its quota, an alarm is raised, though logging continues. The alarm is VOLUME_ALARM_ADVISORY_QUOTA_EXCEEDED. You can view alarms in the Control System or by running the command maprcli alarm list. The default quota is 32 GB.

Effects of the -coalesce parameter

The coalesceparameter represents the interval of time during which READ, WRITE, or GETATTR operations on one file from one client IP address and UID/GID are logged only once for a particular operation, if auditing is enabled.

For example, suppose that a client application reads a single file three times in 6 minutes, so that there is one read at 0 minutes, another at 3 minutes, and a final read at 6 minutes. If the coalesce interval is at least 6 minutes, then only the first read operation is logged. However, if the interval is between 4 minutes, then only the first and third read operations are logged. If the interval is 2 minutes, all three read operations are logged.

Now however, if the client was also writing to the file, irrespective of the coalesce interval for the read operation in the example stated previously, the write operation is logged, as it is a different operation from reading.

The default value is 60 minutes. Setting this field to a larger number helps prevent audit logs from growing quickly.