ORA-01105: mount is incompatible with mounts by other instances ORA-19808: recovery destination parameter mismatch

ORA-01105: mount is incompatible with mounts by other instances
ORA-19808: recovery destination parameter mismatch


Cause: it occurs in RAC environment. issue is due to mismatch of DB_RECOVERY parameters between nodes.
Solution: Make sure the parameters db_recovery_file_dest,db_recovery_file_dest_size are same for all nodes

Example:

Node-1
SQL> show parameter recovery
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string +DATA
db_recovery_file_dest_size big integer 10G
recovery_parallelism integer 0

Node-2
SQL> show parameter recovery
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string +DATA
db_recovery_file_dest_size big integer 100G
recovery_parallelism integer 0

SQL> startup
ORACLE instance started.
Total System Global Area 4275781632 bytes
Fixed Size 2235208 bytes
Variable Size 1694500024 bytes
Database Buffers 2566914048 bytes
Redo Buffers 12132352 bytes
ORA-01105: mount is incompatible with mounts by other instances
ORA-19808: recovery destination parameter mismatch

to clear this error and mount the database set  db_recovery_file_dest_size same on both nodes.
SQL> alter system set db_recovery_file_dest_size = 100G scope=spfile;
 System altered.

SQL> startup
ORACLE instance started.
Total System Global Area 4275781632 bytes
Fixed Size 2235208 bytes
Variable Size 1694500024 bytes
Database Buffers 2566914048 bytes
Redo Buffers 12132352 bytes
Database mounted.
Database opened.