ARCHIVELOG mode considerations

Running an Oracle database in ARCHIVELOG mode is necessary in 24x7 environments. If the archive log destination runs out of space, the database enters into freeze mode until free space is available in the destination directory. The immediate reaction is to delete some of the archive log files. Deleting archive redo logs creates holes in the archived log sequence. This can cause database recovery to fail. Use the following procedures to avoid inadvertently deleting archived logs. Note Oracle documentation should be consulted for exact details of this operation. These procedures are offered as solutions to be considered, and may not be best for all environments. Redirect the archive log destination Maintain two archive log destinations: primary and secondary. Once the primary log is filled to 85 or 90%, a switchover to secondary destination can be performed and vice versa. After switch over, the archived logs in the primary destination can be backed up and subsequently purged from the disk. Move archive logs to a temporary directory Once the archive logs are moved to a temporary directory, Oracle will begin functioning again. Backup the archives logs in the archive log destination directory, and temporary directory, and subsequently purge them to release space. Selectively delete oldest archived logs This is the last resort. List the logs based on time stamp, and selectively delete the oldest archived logs that have already been backed up. (Ensure you back it up before manual delete.) The best practice is to perform Oracle database backups at regular intervals, which can be used to ensure complete recovery while using minimal space.