How do we cleanup the flashback logs from the Flash Recovery Area without any downtime to the production database? Trust me, many people are so confused with these two terms and many actually think they are the same Flash Recovery Area Flash Recovery Area contains all the files you need to completely recover a database from a media failure. They are archivelog files, RMAN backups, control files, flash back logs.
Oracle manages these files automatically when the database experience space pressure in Flash Recovery Area. This feature allows your entire database to be reverted back to a point in time in the past. When you have this feature set, flash back logs will be created. You can limit the number of flashback logs created by setting the retention parameter. In our case we over estimated the Flash Recovery Area in our database and that flashback logs have been growing for several years.
Oracle does not recommend deleting these files from using operating system commands, because that might corrupt your database. Feel free to ask questions on our Oracle forum. Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise.
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Oracle Flashback Logs Cleanup. Step by Step to cleanup flashback logs without any downtime to the production server Have you ever gotten into the situation where flash back logs have been building up for years in the Flash Recovery Area of your database and that you are stumped as to how to clean them up manually?
You are dealing with the production database and that no downtime is allowed unless it is utmost necessity. How do we cleanup the flashback logs from the Flash Recovery Area without any downtime to the production database?
Trust me, many people are so confused with these two terms and many actually think they are the same Flash Recovery Area You can set up Flash Recovery Area for your database and in fact it is best practice to set this up. Flash Recovery Area contains all the files you need to completely recover a database from a media failure. What are those files? Archivelog files, RMAN backups, control files, flash back logs and such.
Keeping the flash recovery area on the same disk as the database area exposes you to loss of both your live database files and backups in the event of a media failure. The flash recovery area is closely related to and can be used in conjunction with two other Oracle features: Oracle Managed Files and Automatic Storage Management.
Oracle Managed Files OMF is a service that automates naming, location, creation and deletion of database files such as control files, redo log files, datafiles and others, based on a few initialization parameters. It can simplify many aspects of the DBA's work by eliminating the need to devise your own policies for such details. The flash recovery area is built on top of OMF, so the flash recovery area can be stored anywhere Oracle-managed files can. ASM consolidates storage devices into easily managed disk groups and provides benefits such as mirroring and striping without requiring a third-party logical volume manager.
You will lose one of the major benefits of the flash recovery area, the automatic deletion of files no longer needed to meet your recoverability goals as space is needed for more recent backups.
However, the other automatic features of OMF will still function. The files in the flash recovery area can be classified as permanent or transient. The only permanent files assuming these are configured to be stored in the flash recovery area are multiplexed copies of the current control file and online redo logs. These cannot be deleted without causing the instance to fail. All other files are transient, because Oracle will generally eventually delete these files, at some point after they become obsolete under the retention policy or have been backed up to tape.
Transient files include archived redo logs, datafile copies, control file copies, control file autobackups, and backup pieces. The larger the flash recovery area is, the more useful it becomes. Ideally, the flash recovery area should be large enough to contain all of the following files:. If providing this much space is impractical, it is best to create an area large enough to keep a backup of the most important tablespaces and all the archived logs not yet copied to tape.
At an absolute minimum, the flash recovery area must be large enough to contain the archived logs that have not been copied to tape. Formulas for estimating a useful flash recovery area size depend upon several factors in your backup and recovery strategy:.
Whether you use a redundancy-based retention policy, or a recovery window-based retention policy;. Whether you plan to use Flashback Database or guaranteed restore points as alternatives to point-in-time recovery to recover from logical errors. Oracle Database Administrator's Guide for details on setting and changing database initialization parameters. This initialization parameter specifies the maximum storage in bytes of data to be used by the flash recovery area for this database.
Block 0 or the OS block header of each Oracle file is not included in this size. For example, if you can configure the flash recovery area on a normal redundancy 2-way mirrored ASM disk group, each file of X bytes occupies 2X bytes on the ASM disk group. This parameter specifies a valid disk location for file creation, which can be a directory on a file system, or Automatic Storage Management disk group. When databases share a single flash recovery area in this fashion, the file system or ASM disk group holding the flash recovery area should be large enough to hold all of the recovery files for all of the databases.
To create a flash recovery area, you can set the necessary parameters in the initialization parameter file PFILE and restart the database. For example, set it to 10 GB:. Set the location of the flash recovery area.
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