Backing Up Oracle - Computing at Cornell

The first statement alter system archive log current forces Oracle to perform
a log switch and to include the present log in the backup set.
If the database is running in ARCHIVELOG MODE and it is not possible to
perform consistent backups, then the backup of the archived redo logs should
be processed immediately after the database backup. But there are other
reasons too to perform the backup of the archived redo logs frequently:
If the file system containing the LOG_ARCHIVE_DESTn has no space left,
Oracle is no more able to archive the logs - and waits until the archiver
process is able to archive again
When a disk fails, it is still possible to recover without (or only a minimum)
of data loss; even when the database backup is already some hours or
days old
10.3.3 Incremental level 0 backup
This example shows how to perform an incremental backup of the database
with RMAN. The level 0 backup is the base for further incremental backups
with a higher level:
run {
allocate channel t1 type 'sbt_tape' parms
'ENV=(DSMO_AVG_SIZE=265)';
allocate channel t2 type 'sbt_tape' parms
'ENV=(DSMO_AVG_SIZE=265)';
backup
incremental level 0
setsize = 265000
format '%d/%t/%s/%p'
tag 'beach inc lvl0 weekly'
database ;
release channel t1 ;
release channel t2 ;
}
In this example, setsize = 265000 specifies the maximum size of a backup
set. It must be greater or equal to the largest datafile in the backup. That is
another option to control the composition of the datafiles in a backup set
166 Backing Up Oracle using Tivoli Storage Management