RMAN-6091: no channel allocated for maintenance (of an appropriate type)

Hello Every one,

Recently, In one of our EBS customer, we came across issue with RMAN backup post CPU Q3 patches  on to 12.1.0.2 instance. The backup failing with below error.

RMAN> delete noprompt archivelog until time 'sysdate -3' backed up 1 times to sbt;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of delete command at 02/03/2019 20:17:05
RMAN-06091: no channel allocated for maintenance (of an appropriate type)

Hence, we've implemented workaround  as per ML 2428682.1

allocate disk channel and delete the datafile copies and archivelog copies.


run {
allocate channel ch1 type 'sbt_tape''";
backup database
include current controlfile ;
}
allocate channel for maintenance device type disk;
crosscheck archivelog all;
delete force noprompt archivelog all;

Workaround::2

============

Apply patch  28432129.

Expected behavior
============

Event after applying the patch 28432129, RMAN may fail with an Error RMAN-6091.

Enhancement Request will be implemented in the future release:" Bug 28593955 : RMAN-6091 ERRORS SEEN EVEN AFTER APPLYING THE PATCH 28432129 "

Note:: This bug 28593955 still yet to implemented by oracle. So we need to apply patch 28432129

Bug fix 28432129 only to allow deletion of archive log and image copies (Not backupsets) , So having some maintenance command mail fail if appropriate channels are not allocated.

Rman never deleted disk backups from SBT channels.

Suggested changes to RMAN scripts to avoid an error.

1) Move all maintenance commands into separate RUN{} or outside RUN{} block as shown in above command and allocate required channels (DISK and TAPE, if RMAN needs to operate on backup files residing on both device types).

2) Have backup commands by allocating whatever device type channels the user wants to create backup files

We should still stick to requirement to have correct device types allocated for maintenance commands operations to work correctly.

Thanks.

Sreeharsha