Check each channel progress for RMAN Backup in Oracle

Check the channel progress with help of gv$session_longops

set line 200 pages 200
col CLIENT_INFO format a10
col "% Complete" format 999.99
select s.inst_id, o.sid, CLIENT_INFO, context, sofar, totalwork,
                    round(sofar/totalwork*100,2) "% Complete"
     FROM gv$session_longops o, gv$session s
     WHERE opname LIKE 'RMAN%'
     AND opname NOT LIKE '%aggregate%'
     AND o.sid=s.sid
     AND totalwork != 0
     AND sofar <> totalwork;

Check Waiting Event time for RMAN Process

set line 200 pages 200
col CLIENT_INFO format a20
col event format a40
col seconds format 999999.99
select inst_id, sid, CLIENT_INFO, seq#, event, state, wait_time_micro/1000000 seconds
 from gv$session where program like '%rman%' and
wait_time = 0 and
 action is not null;

Check RMAN backup progress of each channel
Note: It include table backup progress also if backup_tape_io_slaves=TRUE:

select s.inst_id, a.sid, CLIENT_INFO Ch, a.STATUS,
open_time, round(BYTES/1024/1024,2) "SOFAR Mb" , round(total_bytes/1024/1024,2)
TotMb, io_count,
round(BYTES/TOTAL_BYTES*100,2) "% Complete" , a.type, filename
from gv$backup_async_io a,  gv$session s
where not a.STATUS in ('UNKNOWN')
and a.sid=s.sid and open_time > sysdate - 1;

Check Tape backup progress (only if backup_tape_io_slaves=FALSE)

select s.inst_id, a.sid, CLIENT_INFO Ch, filename, a.type, a.status, buffer_size bsz, buffer_count bfc,
open_time open, io_count
from gv$backup_sync_io a, gv$session s
where a.sid=s.sid and
open_time > sysdate - 1;