Archive log Management Module (AMM)

Owned by KrupeshD (Unlicensed)
Last updated: Dec 31, 2013 by Arjen Visser
5 min read

The Dbvisit Standby Archive Log Management Module fully automates the management and monitoring of the Oracle archive log space on either the primary, standby server or both. Unlike the Oracle database files location, the Oracle archive logs location needs to be monitored and managed constantly to ensure the database continues its optimal operation. If the disk space available to Oracle archive logs is used up, the whole database will "freeze" and not allow any update or insert operation.

Dbvisit Standby Archive Log Management Module includes the following options:

  1. Alerts through email when Oracle archive logs have reached a set threshold of available disk space.
  2. Can delete Oracle archive logs after a set number of days.
  3. Can ensure that only x number of Oracle archive log files remain on server.
  4. Can delete Oracle archive logs after available disk space has been used up to ensure continual database operation.
  5. Ensures the Oracle archive logs have been sent to standby database before removing any logs.
  6. Can integrate with Backup software to ensure logs have been backed up before removing.

Note: Normal backup software should still be used to backup Oracle archive log files to tape or other storage device.

The Dbvisit Standby Archive Log Management Module can be used on the primary server, the standby server or on both. The Dbvisit Standby Archive Log Management Module can either be installed as part of the main Dbvisit Standby configuration or separately through the Dbvisit Standby setup menu. Configuration is always done on the primary server for both the primary server and the standby server. The AMM can be configured separately as part of the initial Dbvisit Standby setup, and can also be configured separately.

As of Dbvisit Standby 6.0.30 managing of archive log files in ASM is supported. Dbvisit Standby uses RMAN to delete logs in multiple archive destinations.

Dbvisit Standby checks if a log has been transferred to the standby server before deleting it on the primary. This check can be turned of by setting AMM_CHECK_TRANSFERRED to No. In case of multiple standby databases, Dbvisit Standby checks if a log has been transferred to all active standby databases before deleting it on the primary. A standby database is considered to be active if a Dbvisit process has run within the last DBV_LAST_RUN_OFFSET days to ship logs to this database from the primary.

To configure AMM choose option 3 from the main dbvisit_setup utility:

 

========================================================= 
Dbvisit Standby Database technology
  http://www.dbvisit.com

Dbvisit Database setup 
  Default values will be shown in [] 
Options: 
1) New Database setup (combines options 2,3,4) 
1a) New RAC Instance setup (combines options 2,3,4) 
2) New Dbvisit Database configuration (DDC) file setup 
3) New Dbvisit Archive Management Module (AMM) setup 
4) New Dbvisit Database repository (DDR) setup 
5) Manage Dbvisit Database repository (DDR) 
6) Update Dbvisit Database configuration (DDC) file 
7) Create Standby Database 
9) Uninstall Dbvisit Database repository (DDR) 
E) Exit 
========================================================= 
Please enter choice : 3

Follow the on-screen instructions to install AMM or please see the  Dbvisit Standby Archive log Management Module (AMM) setup section for description of each step.

Home > Setup > Update Dbvisit > Update Dbvisit Configuration. Choose the AMM settings to update and click on Save Configuration.

Dbvisit Standby Archive Log Management Module variables

The variables that control the Dbvisit Standby Archive Log Management Module (AMM) processing for the primary server are listed here: Primary Archive log Management Module (AMM) 

The variables that control the Dbvisit Standby Archive Log Management Module (AMM) processing for the standby server are listed here: Standby Archive log Management Module (AMM)

Note

  1. The standby server variables work exactly the same as the primary server variables. The standby server variables have the word DEST instead of SOURCE.
  2. In normal circumstances either variable DAYS_TO_KEEP_ARCHSOURCE or NUM_ARCHSOURCE_TO_KEEP will be used, but not both.
  3. The variables DAYS_TO_KEEP_ARCHSOURCE and NUM_ARCHSOURCE_TO_KEEP can be turned off by setting them to 0.
  4. The variable THRESHOLD_ARCHSOURCE can be turned off by setting it to 100.

Dbvisit Standby Archive Log Management Module processing overview

 

The order of precedence in managing the log files are:

  1. If there are log files older than DAYS_TO_KEEP_ARCHSOURCE, then delete these.
  2. If there are more log files than NUM_ARCHSOURCE_TO_KEEP, then delete these (oldest ones first).
  3. If there are more logs that have been backed up by RMAN at least ARCHSOURCE_BACKUP_COUNT times, then delete these.
  4. If the THRESHOLD_ARCHSOURCE < mount point fullness criteria is met, then mark archives for deletion (oldest ones first). The number of archives marked for deletion is HOWMANY_ARCHSOURCE. The archives will only be deleted if DELETE_ARCHSOURCE=Y. After deletion of the archives, and the criteria is still met (THRESHOLD_ARCHSOURCE < mount point fullness), then mark more archives for deletion (number of archives marked for deletion will be again HOWMANY_ARCHSOURCE, and oldest ones first). This process will continue until criteria is no longer met.

If DELETE_ARCHSOURCE=N, then only a warning email will be sent.

No archives will be deleted when the THRESHOLD_ARCHSOURCE < mount point fullness criteria is met.

Setting variable DELETE_ARCHSOURCE=N has no influence over DAYS_TO_KEEP_ARCHSOURCE and NUM_ARCHSOURCE_TO_KEEP. These will still delete archive files when their criteria are met.

Dbvisit Standby Archive Log Management Module log file

The Dbvisit Standby Archive Log Management Module (AMM) produces a separate log file to the Dbvisit Standby database processing. The log file can be found in the same location as Dbvisit Standby database log file. The log file is called <DDC>_arch_management.log. The location is determined by the LOGDIR and LOGDIR_DR settings in the DDC file.

Backup software

To use the Dbvisit Standby Archive log Management Module together with Backup software that backs up the archive logs, the post-processing option of Dbvisit Standby can be used. The post-processing option of Dbvisit Standby runs after Dbvisit Standby has executed, but before the Archive Management Module executes. This ensures that the archive logs have been backed up before they are removed by the Dbvisit Standby Archive log Management Module. The post-processing option can be called either on the primary or on the standby server or both.

On the primary server:

The sequence of events on the primary server is:

  1. Dbvisit Standby pre-processing
  2. Dbvisit Standby transfers the archive logs
  3. Dbvisit Standby post-processing (Backup software can be scheduled here)
  4. Dbvisit Standby Archive log Management Module.

On the standby server:

The sequence of events on the standby server is:

  1. Dbvisit Standby pre-processing
  2. Dbvisit Standby applies the archive logs
  3. Dbvisit Standby post-processing (Backup software can be scheduled here)
  4. Dbvisit Standby Archive log Management Module.

The Backup software can be scheduled as part of the post-processing option. If the Backup software fails, the return code can be trapped and passed back to Dbvisit Standby. This means Dbvisit Standby will alert with a notification and will stop processing. This ensures that the Dbvisit Standby Archive log Management Module will not be executed, and that archive logs will not be deleted before they are backed up.

For more information about post-processing see the Pre- and post-processing section.