If the system tablespace file is missing, it can be restored if there is a backup condition. The database needs to be set to mount state and then Restore/recover datafile
Simulation Experiment:
Sql> select name from V $ datafile;
NAME
-------------------------------------------------------------------- ------------------------------
/u01/app/oracle/oradata/ora11204/datafile/o1_mf_system_9grvc6rn_.dbf
/u01/app/oracle/oradata/ora11204/datafile/o1_mf_sysaux_9grvc6st_.dbf
/u01/app/oracle/oradata/ora11204/datafile/o1_mf_undotbs1_9grvc6t7_.dbf
/u01/app/oracle/oradata/ora11204/datafile/o1_mf_users_9grvc6tr_.dbf
/u01/app/oracle/oradata/ora11204/datafile/o1_mf_example_9grvht2m_.dbf
/home/oracle/data5.dbf
6 rows were selected.
[Oracle @ DB 11204 ~] $ rman target/
Recovery manager:release 11.2.0.4.0-production on Friday September 22 10:51:37 2017
Copyright (c) 1982, Oracle and/or its affiliates. All rights reserved.
Target database:connected to ORA 11204 (Database ID = 1382856929)
Rman> backup Database plus archivelog;
Sql> Shu Immediate
$ mv/u01/app/oracle/oradata/ora11204/datafile/o1_mf_system_9grvc6rn_.dbf/u01/app/oracle/oradata/ora11204/ Datafile/o1_mf_system_9grvc6rn_.dbf.bak
Sql> Startup Mount
[Oracle @ DB 11204 ~] $ rman target/
Recovery manager:release 11.2.0.4.0-production on Friday September 22 11:00:16 2017
Copyright (c) 1982, Oracle and/or its affiliates. All rights reserved.
Target database:connected to ORA 11204 (DBID = 1382856929, not open)
rman> restore datafile 1;
Restore started (start time:17-09-22)
I Use the target database control file instead of the recovery catalog
Channel:ora_disk_1 assigned
Channel Ora_disk_1:sid = ten Device Type = DISK
Channel ora_disk_1:restoring the data file Backup set is starting
Channel ora_disk_1:specifies The data file to being restored from the backup set
Channel ora_disk_1:restores data File 00001 to/u01/app/oracle/oradata/ora11204/datafile/o1_mf_system_9grvc6rn_.dbf
Channel Ora_disk_1:backup piece/u01/app/oracle/fast_recovery_area/ora11204/backupset/2017_09_22/o1_mf_nnn Df_tag20170922t105151_dw8v5rbq_.bkp
Channel ora_disk_ 1:piece handle =/U 01/app/oracle/fast_recovery_area/ora 11204/backupset/2017 _ 09 _ 22/ O 1 _ MF _ nnndf _ TAG 20170922 T 105151 _ DW 8 V 5 RBQ _. BKP tag = tag 20170922 T 105151
Channel ora_disk_1:backup piece 1 has been restored
Channel Ora_disk_1:restore complete. Elapsed time:00:01:35
Restore completed (completion time:17-09-22)
Rman>
rman> recover datafile 1;
Recover started (start time:17-09-22)
Use of channel Ora_disk_1
Media Recovery is starting
Media recovery is completed. Elapsed time:00:00:01
Recover completed (completion time:17-09-22)
Rman> exit
Recovery Manager has completed.
[Oracle @ DB 11204 ~] $
[Oracle] File loss for System Tablespace