backup as copy incremental level 0 tag 'roll_update' database;
On the second day create a incremental level 1 of the database
backup incremental level 1 for recover of copy with tag 'roll_update' database;
On the thrid day use the second day incremental level 1 backup to roll forward the first day level 0 backup and then take a new incremental level 1 backup and repeat this step.
run{
recover copy of database with tag 'roll_update';
backup incremental level 1 for recover of copy with tag 'roll_update' database;
}
The whole thing could be simplified with
run{
recover copy of database with tag 'roll_update';
backup incremental level 1 for recover of copy with tag 'roll_update' database;
}
Points to note.
1. The BACKUP INCREMENTAL LEVEL 1... FOR RECOVER OF COPY WITH TAG... command does not actually always create a level 1 incremental backup. If there is no level 0 image copy backup of an particular datafile, then executing this command creates an image copy backup of the datafile on disk with the specified tag instead of creating the level 1 backup. Thus, the first time the script runs, it creates the image copy of the datafile needed to begin the cycle of incremental updates. In the second run and all subsequent runs, it produces level 1 incremental backups of the datafile.
2. The RECOVER COPY OF DATABASE WITH TAG... command causes RMAN to apply any available incremental level 1 backups to a set of datafile copies with the specified tag. If there is no incremental backup or no datafile copy, the command generates a message but does not generate an error. The first time the script runs, this command has no effect, because there is neither a datafile copy nor a level 1 incremental backup. The second time the script runs, there is a datafile copy (created by the first BACKUP command), but no incremental level 1 backup, so again, the command has no effect. On the third run and all subsequent runs, there is a datafile copy and a level 1 incremental from the previous run, so the level 1 incremental is applied to the datafile copy, bringing the datafile copy up to the checkpoint SCN of the level 1 incremental.
3. Each time a datafile is added to the database, an image copy of the new datafile is created the next time the script runs. The time after that, the first level 1 incremental for that datafile is created, and on all subsequent runs the new datafile is processed like any other datafile.
4. Tags must be used to identify the incremental level 0 datafile copies created for use in this strategy, so that they do not interfere with other backup strategies you implement. If you have multiple incremental backup strategies in effect, RMAN cannot unambiguously create incremental level 1 backups unless you tag level 0 backups. The incremental level 1 backups to apply to those image copies are selected based upon the checkpoint SCNs of the image copy datafiles and the available incremental level 1 backups. (The tag used on the image copy being recovered is not a factor in the selection of the incremental level backups.)
more on incremental backups
