RMAN> restore spfile from autobackup;
Starting restore at 03-APR-19
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190403
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190402
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190401
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190331
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190330
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190329
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20190328
channel ORA_DISK_1: no AUTOBACKUP in 7 days found
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190403
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190402
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190401
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190331
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190330
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190329
channel ORA_DISK_2: looking for AUTOBACKUP on day: 20190328
channel ORA_DISK_2: no AUTOBACKUP in 7 days found
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of restore command at 04/03/2019 16:27:24
RMAN-06172: no AUTOBACKUP found or specified handle is not a valid copy or piece
解决方法：
RMAN> restore spfile from '/u01/app/oracle/fast_recovery_area/PROD2/autobackup/2019_04_03/o1_mf_s_1004630646_gb8t7ro3_.bkp';
Starting restore at 03-APR-19
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_2: skipped, AUTOBACKUP already found
channel ORA_DISK_1: restoring spfile from AUTOBACKUP /u01/app/oracle/fast_recovery_area/PROD2/autobackup/2019_04_03/o1_mf_s_1004630646_gb8t7ro3_.bkp
channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete
Finished restore at 03-APR-19
原因是oracle无法识别db_recovery_file_dest参数，为避免出现以上报错，可以先设置db_recovery_file_dest参数
设置方法：
alter system set db_recovery_file_dest_size=4g;
alter system set db_recovery_file_dest='/u01/app/oracle/fast_recovery_file_dest';
2019-4-3 18:40