1. How to change the current location for archivelogs:
SQL> alter system set log_archive_dest_1='LOCATION=/u20/oracle/data1';
If you want to use the Flash Recovery Area (FRA) as your archivelog destination, wise to use really with RMAN as it will delete obsolete archivelogs based on the backup retention policy, then use this command. Otherwise you have to set up manual ways of deleting old obsolete archivelogs.
2. How to Use Flash Recovery Area (FRA) as your archivelog location:
(First set up flash recovery area)
SQL> alter system set log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST' ;
The parameter USE_DB_RECOVERY_FILE_DEST is very good. It keeps things tidy. Together with the autobackup and backupset directories in the FRA it will also create a directory called archivelogs and will put the archivelogs in there!
Given the FRA as:
oracle@machine:/usr/local/oracle/flash_recovery_area/TESTDW0$ ls -lrt
drwxr-x--- 9 oracle oinstall 4096 2007-11-07 07:45 backupset
drwxr-x--- 9 oracle oinstall 4096 2007-11-07 07:45 autobackup
drwxr-x--- 4 oracle oinstall 4096 2007-11-07 07:45 archivelog
When you decide to use FRA for your archivelogs, you might want to move the existing archivelogs into FRA after you have set the destination as above. When you do that you will need to let RMAN know where the archivelogs are? That is where is their new location you can achieve that with the command
RMAN> catalog archivelog '/your/new/location/thearchivelogfile';
Docs say this: http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmcatdb002.htm#sthref941
Otherwise you will probably get ane error like:
... specification does not match any archive log in the recovery catalog
Which means that the controlfile does not know about the new location of your archivelogs.