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Database Administration
Protecting Your Data : Backing Up a Database : Using database quiet points
 

Using database quiet points

If you use your operating system's disk mirroring to provide data redundancy as part of your backup and recovery strategy, you can use database quiet points, on systems with an Enterprise database license, to maintain database consistency during an OS mirror fracture or split operation on an active online database.
To maintain database consistency during an OS mirror fracture or split operation on an active online database:
1. Use the PROQUIET command to enable a database quiet point.
Enter the command with the syntax shown:
proquiet dbname enable
In this command, dbname specifies the name of the database for which you are enabling a database quiet processing point.
During a database quiet processing point all file write activity to the database is stopped. Any processes that attempt to start a transaction while the quiet point is enabled must wait until you disable the database quiet processing point.
2. Use an operating system utility to perform the OS mirror fracture or split operation.
Upon successful completion of this command, the fractured disk contains a duplicate of the active online database.
3. Use the PROQUIET command to disable the database quiet point.
Enter the command with the syntax shown:
proquiet dbname disable
In this command, dbname specifies the name of the database for which you are disabling a database quiet processing point.
For more information and the complete syntax for PROQUIET, see Startup and Shutdown Commands.
4. Update the structure description (.st) file of the fractured version of the database. Replace the logical location reference (which still references the active database) with the physical location reference of the fractured mirror.
5. Run the PROSTRCT REPAIR command on the fractured version of the database with the updated .st file.
Enter the command with the syntax shown:
prostrct repair dbname [description-file]
In this command:
*dbname specifies the name of the database for which you are repairing the extent list and master block.
*description-file specifies the name of the structure description (.st) file.
Running PROSTRCT REPAIR updates the shared memory and semaphore identification information to reflect the offline status of the fractured version of the database, and update the file list information with the information in the updated .st file
6. Use the PROBKUP utility with the -norecover startup parameter to back up the fractured version of the database.
Enter the command with the syntax shown:
probkup dbname -norecover
In this command, dbname specifies the name of the of the fractured version of the database.
Note: The -norecover parameter prevents PROBKUP from performing crash recovery or switching to a new AI extent as part of the backup process. Use of the -norecover parameter is noted as an entry in the .lg file.