Your database is running in NOARCHIVELOG mode. Every night there is a backup taken using RMAN. During your startup this morning you received an error regarding DISK 3 on your server.This is the location of your data file for the SYSTEM tablespace. Which option is open to you?
The data file needs to be restored by using operating system commands, because a data file movement must take place, and then the database can be recovered from RMAN.
The data file needs to be restored by using operating system commands, since a data file movement must take place, and then the database must be recovered manually.
From RMAN you can issue the commands RESTORE and RECOVER. RMAN automatically restores the data file on DISK 3 to another disk, based upon utilization statistics.
From RMAN you can issue a SET NEWNAME command to update the data file location information in the control file, and then issue the RESTORE and RECOVER commands to recover the database.
In NOARCHIVELOG mode with a damaged SYSTEM data file, use SET NEWNAME in RMAN to redirect the restore to a new location, then RESTORE and RECOVER. SET NEWNAME updates the control file with the new data file location. OS-level restore commands alone won't work because RMAN needs to know the new location. RMAN doesn't automatically choose disk locations based on utilization - you must specify them.
When a datafile needs to move to a different location (because the original disk is unavailable), RMAN's SET NEWNAME command tells the control file where to find the relocated datafile once it's restored there. You then run RESTORE to physically copy the datafile to the new location and RECOVER to apply any changes, bringing it in sync with the rest of the database before opening it. The other options either require unsupported manual/OS-level file surgery or assume RMAN can auto-pick a new disk, which it cannot do without SET NEWNAME.