ODA/KVM: rman-03009 ora-19504 during database recovery

During the restore of databases, where the backup is located on a NFS mount, the error rman-03009 ora-19504 ora-17502 may occur.

RMAN-03009: failure of Control File and SPFILE Autobackup command on D1 channel at 08/22/2023 18:42:36
ORA-19504: failed to create file "/mnt/backup/.../c-1923627618-20230822-01"
ORA-17502: ksfdcre:9 Failed to create file /mnt/backup/.../c-1923627618-20230822-01

The error is misleading. There is no issue with the directory.

This is a dNFS bug. As a workound, disable dNFS all on all db nodes:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk dnfs_off