4.2 Understanding Automated Cell Maintenance

The Management Server (MS) includes a file deletion policy based on the date.

When there is a shortage of space in the Automatic Diagnostic Repository (ADR) directory, then MS deletes the following files:

• All files in the ADR base directory older than 7 days.
• All files in the LOG_HOME directory older than 7 days.
• All metric history files older than 7 days.

The retention period of seven days is the default. The retention period can be modified using the metricHistoryDays and diagHistoryDays attributes with the ALTER CELL command. The diagHistoryDays attribute controls the ADR files, and the metricHistoryDays attribute controls the other files.

If there is sufficient disk space, then trace files are not purged. This can result in files persisting in the ADR base directory past the time limit specified by diagHistoryDays.

In addition, the alert.log file is renamed if it is larger than 10 MB, and versions of the file that are older than 7 days are deleted if their total size is greater than 50 MB.

MS includes a file deletion policy that is triggered when file system utilization is high. Deletion of files in the / (root) directory and the /var/log/oracle directory is triggered when file utilization is 80 percent. Deletion of files in the /opt/oracle file system is triggered when file utilization reaches 90 percent, and the alert is cleared when utilization is below 85 percent. An alert is sent before the deletion begins. The alert includes the name of the directory, and space usage for the subdirectories. In particular, the deletion policy is as follows:

• The /var/log/oracle file systems, files in the ADR base directory, metric history directory, and LOG_HOME directory are deleted using a policy based on the file modification time stamp.

  • Files older than the number of days set by the metricHistoryDays attribute value are deleted first
  • Successive deletions occur for earlier files, down to files with modification time stamps older than or equal to 10 minutes, or until file system utilization is less than 75 percent.
  • The renamed alert.log files and ms-odl generation files that are over 5 MB, and older than the successively-shorter age intervals are also deleted.
  • Crash files in the /var/log/oracle/crashfiles directory that are more than one day old can be deleted. If the space pressure is not heavy, then the retention time for crash files is the same as for other files. If there are empty directories under /var/log/oracle/crashfiles, these directories are also deleted.

• For the /opt/oracle file system, the deletion policy is similar to the preceding settings. However, the file threshold is 90 percent, and files are deleted until the file system utilization is less than 85 percent.

• When file system utilization is full, the files controlled by the diagHistoryDays and metricHistoryDays attributes are purged using the same purging policy.

• For the / file system, files in the home directories (cellmonitor and celladmin), /tmp, /var/crash, and /var/spool directories that are over 5 MB and older than one day are deleted.

Every hour, MS deletes eligible alerts from the alert history using the following criteria. Alerts are considered eligible if they are stateless or they are stateful alerts which have been resolved.

• If there are less than 500 alerts, then alerts older than 100 days are deleted.

• If there are between 500 and 999 alerts, then the alerts older than 7 days are deleted.

• If there are 1,000 or more alerts, then all eligible alerts are deleted every minute.

Note:

Any directories or files with SAVE in the name are not deleted.