Imagine with me that you are working on the database and suddenly a disk failure occurs, which causes the loss of all the online log files,

knowing that you did not lose any of the Data Files and Control Files, but in fact we cannot perform a recovery for the database since we lost all online files because we need it in the recovery process,

so what is the solution? Here are the steps:-

1- SHUT ABORT the database.

2- Restore all Data Files and Control Files from the Full Backup that has all the archive files required for the recovery operations.

3- Then we open the database in MOUNT mode.

STARTUP MOUNT;

 4- We do an INCOMPLETE RECOVERY for the database.

Alter database recover automatic using backup controlfile until cancel;
Recover cancel;

5- Open the database in RESETLOGS mode.

ALTER DATABASE OPEN RESETLOGS;

When you open the database in RESETLOGS mode, Oracle automatically creates ONLINE LOG FILES. This can be seen through the operating system or through the following query:

SELECT GROUP#,MEMBERS,STATUS,SEQUENCE# FROM V$LOG;

But have you ever thought about what would happen if you had Multiplexing the log files on multiple disks?

Of course, you would now be spared all this effort to restore the database and you might have lost some of your data.