ORA-00245: control file backup failed; in Oracle RAC, target might not be on shared storage

rman backup failed with below error

Error:

channel c4: backup set complete, elapsed time: 00:00:11

RMAN-03009: failure of backup command on c2 channel at 10/20/2020 01:00:30

ORA-00245: control file backup failed; in Oracle RAC, target might not be on shared storage

continuing other job steps, job failed will not be re-run

channel c1: finished piece 1 at Oct 20 1 01:04:35

piece handle=/backup/r/full/full_PRDDB31_1086397215_50020_1 tag=TAG2013401T10017 comment=NONE

channel c1: backup set complete, elapsed time: 00:04:20

released channel: c1

released channel: c2

released channel: c3

released channel: c4

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03009: failure of backup command on c2 channel at 10/20/2020 01:00:30

ORA-00245: control file backup failed; in Oracle RAC, target might not be on shared storage

Cause: Backup location not accessible from all cluster nodes 

Solution:

Mount  /backup  from all nodes and check permissions on backup folder