RMAN-06091: no channel allocated for maintenance

RMAN> delete obsolete;

the following error occurs:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of delete command at 18/01/2021 22:04:21
RMAN-06091: no channel allocated for maintenance (of an appropriate type)

Cause

Tape channel had not being allocated when attempt to delete obsolete backup on tape or disk.

Using the following command to verify that there are backup sets on tape.

RMAN> list backup;

This will show you the backup details informing you which channel device type that needs to be allocated.

Solution

To implement the solution, please execute the following steps:

Please run the following commands to delete obsolete backup sets on both disk and tape:
RMAN> allocate channel for maintenance type disk;
RMAN> allocate channel for maintenance device type ‘sbt_tape’ PARMS ‘…’;
==>Please change ‘…’ to your actual tape params

RMAN> delete force obsolete;

If you want to delete obsolete backup sets on disk, you can use the following commands:
RMAN> allocate channel for maintenance type disk;
RMAN> delete obsolete device type disk;