The recovery catalog views are derived from these tables. Note that the recovery catalog views are not normalized or optimized for user queries. In general, the recovery catalog views are not as user-friendly as the RMAN reporting commands. If you have ten different target databases registered in the same recovery catalog, then any query of the catalog views show the metadata for all incarnations of all ten databases.
You often have to perform complex selects and joins among the views to extract usable information about a database incarnation. Posted in oracle Leave a Comment.
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Just e-mail: and include the URL for the page. All rights reserved by Burleson. One-off configuration of device type and parallelism. This chapter explains advanced RMAN backup procedures. This chapter contains the following topics:. This control is helpful when backing up very large files.
This control is especially useful when you use a media manager that has restrictions on the sizes of files, or when you must back up very large files. RMAN attempts to limit all backup sets to this size. If the backup fails partway through, then you can use the restartable backup feature to back up only those files that were not backed up during the previous attempt. RMAN displays an error stack such as the following:. Backup piece size is an issue in those situations where it exceeds the maximum file size of the file system or media management software.
The following example backs up archived logs to tape, limiting the size of each backup set to MB:. A file section is a contiguous range of blocks in a file. This type of backup is called a multisection backup. The purpose of multisection backups is to enable RMAN channels to back up a single large file in parallel.
RMAN divides the work among multiple channels, with each channel backing up one file section in a file. Backing up a file in separate sections can improve the performance of backups of large datafiles. If a multisection backup completes successfully, then none of the backup sets generated during the backup contain a partial data file. If a multisection backup is unsuccessful, then it is possible for the RMAN metadata to contain a record for a partial backup set.
RMAN does not consider partial backups for restore and recovery. If you specify a section size that is larger than the size of the file, then RMAN does not use multisection backup for the file.
If you specify a small section size that would produce more than sections, then RMAN increases the section size to a value that results in exactly sections. For example, suppose that the users tablespace contains a single data file of MB. You can break up the data file in this tablespace into file sections as shown in the following example:. In this example, each of the three SBT channels backs up a MB file section of the users data file.
When certain criteria are met, RMAN skips backups of files that are identical to files that are already backed up. For the following scenarios, assume that you configure backup optimization and a retention policy as shown in the following example. Example Configuring Backup Optimization. With RMAN configured as shown in Example , you run the following command every night to back up the database to tape:.
Because backup optimization is configured, RMAN skips backups of offline and read-only data files only if the most recent backups were made on or after the earliest point in the recovery window. RMAN does not skip backups when the most recent backups are older than the window. For example, optimization ensures you do not end up with a new backup of a read-only data file every night, so long as one backup set containing this file exists within the recovery window.
Assume that you want to back up all the archived logs every night, but you do not want to have multiple copies of each log sequence number. With RMAN configured as shown in Example , you run the following command in a script nightly at 1 a. RMAN skips all logs except those produced in the last 24 hours. In this way, you keep only one copy of each archived log on tape. In Oracle Secure Backup, a media family is a named group of volumes with a set of shared, user-defined attributes.
In this scenario, you back up logs that are not on tape to one media family, then back up the same logs to a second media family. Finally, you delete old logs. With RMAN configured as shown in Example , run the following script at the same time every night to back up the logs generated during the previous day to two separate media families.
If your goal is to delete logs from disk that have been backed up two times to SBT, then the simplest way to achieve the goal is with an archived redo log deletion policy. The following one-time configuration specifies that archived redo logs are eligible for deletion from disk if two archived log backups exist on tape:. Assume a more sophisticated scenario in which your goal is to back up the archived logs to tape every day.
You are worried about tape failure, however, so you want to ensure that you have more than copy of each log sequence number on an separate tape before you perform your weekly deletion of logs from disk. This scenario assumes that the database is not using a fast recovery area. Every Friday evening you create an additional backup of all archived logs in a different media family. At the end of the backup, you want to delete all archived logs that have at least two copies on tape.
So you run the following script:. Table Effects of Daily and Weekly Scripts. Because the secondary tape is offsite, you do not want RMAN to use it for recovery, so you can mark the backup as unavailable:. You can specify parameters to prevent termination, as listed in Table SKIP Options. Offline datafiles. Some offline datafiles can still be read because they exist on disk. Others have been deleted or moved and so cannot be read, making them inaccessible.
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