RMAN manual allocation of parallel channels

The article directories
RMAN manual allocation of parallel channels 1. View data file temporary file location 2. Manual channel allocation 3. How to set parallelism to 3

1. View temporary file location of data file

RMAN> report schema;

Report of database schema for database with db_unique_name PROE

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    750      SYSTEM               ***     /u01/app/oracle/oradata/proe/system01.dbf
2    600      SYSAUX               ***     /u01/app/oracle/oradata/proe/sysaux01.dbf
3    90       UNDOTBS1             ***     /u01/app/oracle/oradata/proe/undotbs01.dbf
4    6        USERS                ***     /u01/app/oracle/oradata/proe/users01.dbf
5    346      EXAMPLE              ***     /u01/app/oracle/oradata/proe/example01.dbf
6    20       TEST_1               ***     /u01/app/oracle/oradata/proe/test_1.dbf
7    100      TBS_TRAN             ***     /u01/app/oracle/oradata/proe/tbs_tran01.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    29       TEMP                 32767       /u01/app/oracle/oradata/proe/temp01.dbf

2. Manually assign channels

RMAN> run{
2> allocate channel ch1 device type disk format '/u01/app/backup/tbs_%U';
3> backup tablespace TBS_TRAN;
4> release channel ch1;
5> }

allocated channel: ch1
channel ch1: SID=1144 device type=DISK

Starting backup at 10-AUG-20
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00007 name=/u01/app/oracle/oradata/proe/tbs_tran01.dbf
channel ORA_DISK_1: starting piece 1 at 10-AUG-20
channel ORA_DISK_1: finished piece 1 at 10-AUG-20
piece handle=/u01/app/oracle/fast_recovery_area/PROE/backupset/2020_08_10/o1_mf_nnndf_TAG20200810T140602_hm1rybq5_.bkp tag=TAG20200810T140602 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 10-AUG-20

3. How to set the parallelism of 3

RMAN> run{
2> allocate channel ch1 device type disk format '/u01/app/backup1/bak1_%U';
3> allocate channel ch2 device type disk format '/u01/app/backup2/bak2_%U';
4> allocate channel ch3 device type disk format '/u01/app/backup3/bak3_%U';
5> backup 
6> (datafile 1 channel ch1)
7> (datafile 2,3 channel ch2)
8> (datafile 4,5,7,8,9,14 channel ch3);
9> release channel ch1;
10> release channel ch2;
11> release channel ch3;
12> }