How to arrange a backup set in RMAN

Question

I have configured the RMAN parametrs for my database. when I'm going to take the backups it gives an error called no backupset found
screen is like this
RMAN> BACKUP BACKUPSET ALL;
Starting backup at 25-JUL-07
using channel ORA_DISK_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 07/25/2007 08:41:42
RMAN-06462: no backupsets found on device DISK that match specification
my RMan configuration is below
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO 'G:\backup\cf_ba
ckup\cf%F';
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO '%F'; # defa
ult
CONFIGURE DEVICE TYPE 'SBT_TAPE' PARALLELISM 3 BACKUP TYPE TO BACKUPSET;
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT 'G:\backup\%U';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO 'G:\ORACLE\PRODUCT\10.1.0\DB_2\DATABASE\S
NCFNEW10G.ORA'; # default
how would I create a backupset in this case
thanks
buddhike

Answer 1

Sigh. You wouldn't be willing to spend some time in the manuals, would you?
RMAN actually consists of 2 parts:
- the shell, which you invoke;
- the rman procedure, which is inside the Oracle database kernel.
Your request is sent to the kernel, and is executed by the kernel. Therefore the kernel must be running.
If your database is in ARCHIVELOG mode, you can do a hot backup - simply go into RMAN and tell it to backup the database.
However, if you are in NOARCHIVELOG mode, you must ensure that nothing can change in the database files. Therefore you can not have the database in the OPEN state.
In the NOARCHIVELOG mode, you MUST shut down the database, then re-start it using STARTUP MOUNT. Then you can get RMAN to do it's backup, after which you can then ALTER DATABASE OPEN;
The other advantage of ARCHIVELOG mode is that the database can be restored to virtually any point in time, whereas a NOARCHIVELOG database can ONLY be restored to the backup point in time.
However, the advantage does come at a price - disk space for the archive logs which are used to reconstruct any point in time.