Planning Storage Spaces to Optimize Backup Performance

If your database contains many static tables with read-only data, consider placing these tables and any indexes on those tables in dbspaces that are separate from those dbspaces containing the data you want to continue to modify. After loading the read-only data, you can use the onutil ALTER DBSPACE STATIC command to flag dbspaces that contain such read-only data as read-only (static) dbspaces.

Flagging dbspaces containing static data as read-only (static) dbspaces has two advantages:

• The database server disallows attempts to modify data stored in read-only dbspaces, thus protecting the data from accidental modification. Any attempt to modify such data will fail with ISAM error 21501.
• You can request the ON-Bar Backup and Restore utility to avoid archiving read-only dbspaces if the dbsapces have already been backed up. Do this by using the onbar -S option. In a data warehouse environment containing large amounts of static data, avoiding repeated backups of read-only data can greatly improve the performance of backups and reduce the consumption of backup media.

For more information on the ON-Bar backup and restore utility, see the IBM Informix: Backup and Restore Guide.

For more information on the onutil utility, see the IBM Informix: Extended Parallel Server Administrator's Reference.