How to restore the spfile in oracle database

To restore spfile,  the auto backup of your control file should be enabled and have already taken a backup after enabling the controlfile auto backup feature of RMAN.

RMAN> configure controlfile autobackup on;

We can restore the spfile either using a recovery catalog or RMAN autobackup from default location(FRA).

1. Using Recovery Catalog:

   $ rman target / catalog rcat/rcat@rcatdb
   RMAN> startup nomount;
   RMAN> restore spfile;
   RMAN> startup force;

2. RMAN Auto Backup in Default Location:

   $ rman target /
   RMAN> startup force nomount;
   RMAN> set dbid 1436686810;
   RMAN> restore spfile from autobackup;
   RMAN> startup force;

We can also restore spfile from a non-default location of RMAN controlfile autobackup:

$ rman target /
RMAN> set dbid 768943403;
RMAN> startup force nomount;
RMAN> restore spfile from
'+FRA/autobackup/2022_09_25/o2_mf_s_443335437_31fbttrl_.bkp';
RMAN> startup force;