How to change the control_files parameter used in the spfile

Mind your syntax when you are changing certain multi-value parameters directly in the spfile. Oracle will tell you that the syntax is accepted, but it will give you an error later. The following example is from an attempt to change the control_files parameter.

Won't work:

SQL> alter system set control_files='/oradata/proddb01/control01.ctl, /fra/proddb01/control02.ctl' scope=spfile;

System altered.

During mount stage, this will give you the following message in the database's alert log:

ORA-205 signalled during: ALTER DATABASE   MOUNT...
ORA-00202: control file: /oradata/proddb01/control01.ctl, /fra/proddb01/control02.ctl
ORA-27037: cannot obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 7

Works:

SQL> alter system set control_files='/oradata/proddb01/control01.ctl','/fra/proddb01/control02.ctl' scope=spfile;

System altered.

You should enclose both values within ' ' apostroph characters.