ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

I wanted to turn archiving for my database. To turn on archive log mode the database must be mounted, but not open. If the database is already open, first shutdown the database using "shutdown" or "shutdown immediate". If you use "shutdown abort" to shutdown the database, then while running the SQL> alter database archivelog; you will get the ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

The easiest way to get around this would be to start the database again using startup, and the shutting it again using "shutdown" or "shutdown immediate". This will do the trick.

-bash-3.2$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.1.0 Production on Wed Jun 8 12:06:23 2011 Copyright (c) 1982, 2009, Oracle.  All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> archive log list; Database log mode              No Archive Mode Automatic archival             Disabled Archive destination            /u01/app/oracle/product/11.2.0/dbhome_1/dbs/arch Oldest online log sequence     132361 Current log sequence           132363 SQL> alter database archivelog; alter database archivelog * ERROR at line 1: ORA-01126: database must be mounted in this instance and not open in any instance SQL> shutdown abort; ORACLE instance shut down. SQL> startup mount; ORACLE instance started. Total System Global Area 2.6991E+10 bytes Fixed Size                  2213976 bytes Variable Size            1.7985E+10 bytes Database Buffers         8858370048 bytes Redo Buffers              145174528 bytes Database mounted. SQL> alter database archivelog; alter database archivelog * ERROR at line 1: ORA-00265: instance recovery required, cannot set ARCHIVELOG mode SQL> shutdown; ORA-01109: database not open Database dismounted. ORACLE instance shut down. SQL> SQL> startup mount; ORACLE instance started. Total System Global Area 2.6991E+10 bytes Fixed Size                  2213976 bytes Variable Size            1.7985E+10 bytes Database Buffers         8858370048 bytes Redo Buffers              145174528 bytes Database mounted. SQL> alter database archivelog; alter database archivelog * ERROR at line 1: ORA-00265: instance recovery required, cannot set ARCHIVELOG mode SQL> shutdown; ORA-01109: database not open Database dismounted. ORACLE instance shut down. SQL> startup; ORACLE instance started. Total System Global Area 2.6991E+10 bytes Fixed Size                  2213976 bytes Variable Size            1.7985E+10 bytes Database Buffers         8858370048 bytes Redo Buffers              145174528 bytes Database mounted. Database opened. SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount; ORACLE instance started. Total System Global Area 2.6991E+10 bytes Fixed Size                  2213976 bytes Variable Size            1.7985E+10 bytes Database Buffers         8858370048 bytes Redo Buffers              145174528 bytes Database mounted. SQL> alter database archivelog; Database altered. SQL> SQL>  archive log list; Database log mode              Archive Mode Automatic archival             Enabled Archive destination            /u01/app/oracle/product/11.2.0/dbhome_1/dbs/arch Oldest online log sequence     132362 Next log sequence to archive   132364 Current log sequence           132364 SQL>