Backup L0 and L1 Cumulative - Module Oracle Database - High backup runtime

Hello everyone.

I`m new on this community and i need your help.

We have a Oracle database and the size is 30 TB

What the best configuration for L0 Cumulative backup ?

- The database backup during +40 hours and executed by ddboost device. I need reduce the time exec.

All pieces/channels complete in 15~16 hours, only one channel remains running and affects the backup schedule

cfg:

Backup Database Level 0 Cumulative - INCLUDE CURRENT CONTROLFILE - PLUS ARCHIVELOG DELETE INPUT - 12 RMAN channels - Parallelism 400 ( I think this option is wrong ) - Priority 500 - Using client direct (Backup archives running every 30 minutes / Backup Cumulative L0 one day a week / Cumulative L1 all day, skipping day at L0 exec)

And the backup Cumulative Level 0 or 1 sometimes failed with log below

RMAN-10038: database session for channel CH1 terminated unexpectedly channel CH1 disabled, job failed on it will be run on another channel

I think the parallelism(400) option is affecting backups and the entire environment.

Any idea ? Thanks guys