One time setting
RMAN> show all;
RMAN configuration parameters for database with db_unique_name ORCL are:
...
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
...
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
...
RMAN> CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
new RMAN configuration parameters:
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
new RMAN configuration parameters are successfully stored
You don't have to add compressed syntax for each RMAN script like the statement introduced below.
Run-time setting
RMAN> backup as compressed backupset incremental level 0 database plus archivelog;
Note: The incremental level 1 backupset takes very little to no advantages of the compressed feature. But full backup (or level 0) can make 5:1 compression ratio in one of my databases.
Another topic related to compression is about backup encryption, I talked about it in this post: How to Backup and Restore Under Encryption and Compression
Compress backup set take longer time almost double. We have almost 32TB size database and approximately take 10 hours to backup. In case if we try compress the time increase more than double.
Yes, it’s possible. Paralleled compression is a CPU intensive task, more powered CPU get less time consuming.