Several concepts-about RMAN backup

For more information, see

I am here to ask for advice.

1. Under what circumstances do I need to redo the control file? For example, if I accidentally delete a data file and there is no backup, and there is no content in the time and space of the data file, When I redo the control file, will the system read the System View and record the files in the current normal state so that the database can be used for recovery.

2. When backing up a database (related to RMAN), we can see what level 0 backup, level 1 backup, and so on, what level 0 backup and Level 1 backup seem to have similar words, such, when looking at Incremental Backup (or the part in RMAN), what does it mean to say "at the same level or lower level?

3. Is there any relationship or difference between the Incremental Backup concept mentioned in Exp for Incremental backup, cumulative backup, and rman?

Author:Snowhite2000 Time:02-04-06 :53

I want to answer your questions on the forum.

1. Under what circumstances do I need to redo the control file? For example, if I accidentally delete a data file and there is no backup, and there is no content in the time and space of the data file, When I redo the control file, will the system read the System View and record the files in the current normal state so that the database can be used for recovery.

Seeing your problem, Bai xuehongchen has been desperately thinking that the control file was re-established once because the database name needs to be modified.

In what situations do we need to re-establish the control file:

1. All control files in the database are lost or damaged (this seems unlikely, at least I have never encountered any loss or damage)

2. You need to change some parameter defined during database creation, such
Maxdatafiles, maxlogfiles, and maxloghistory.

3. just like Bai Xue, I want to change the database name or change the location of all datafiles and logfiles, but I want to use recreate control file to complete it, for example, if you clone a database to another machine with the same operating system, the system does not have the drive disk where your current datafile is located. (For example, datafiles are all stored in F drive on system A, And you cloned to system B, only C drive is available ). Of course, you can do this using other methods, such as export/import. You can also play the recreate control file game. However, the read-only tablespaces game is not very fun. Although the solution is also very simple.

4. I almost forgot. If your database is ill and you want Oracle support to help you, and if he asks you to recreate the control file, you probably won't have a choice.

I haven't thought of other situations yet. The situation you mentioned in the question does not need to be implemented through recreate control file.

Snow White

Author:Snowhite2000 Time:02-04-06 07:02

2. When backing up a database (related to RMAN), we can see what level 0 backup, level 1 backup, and so on, what level 0 backup and Level 1 backup seem to have similar words, such, when looking at Incremental Backup (or the part in RMAN), what does it mean to say "at the same level or lower level?

For this question, I want to explain first what is the differential incremental backup and cumulative incremental backup of RMAN.

Differential Incremental Backup: it refers to the backup of blocks that has changed since the last backup of the same level or lower level. (I'm learning your problem ).

Cumulative Incremental Backup: refers to the backup of blocks that has changed since the last backup of the same level minus the level or lower level.

For the backup level, only the level 0 Incremental backup is a basic backup, which is a full backup. The numbers of other levels are relative and there is no fixed requirement.

For example:
Differential Incremental Backup
Sunday: Level 0
Monday: Level 5
Tuesday: Level 5
Wednesday: Level 3
It is interpreted as: Full backup is performed on Sunday, and blocks that have changed since Sunday backup are backed up on Monday. for Tuesday, the most recent backup of the same level or low level is Monday (both level 5 ), therefore, it is to back up blocks with changes after the backup on Monday; Level 3 on Wednesday, and level 0 on Sunday for the last backup at the same level or lower, therefore, it is to back up blocks that has changed since the backup on Sunday. If you change Level 5 to level 2 and level 3 to level 1, the result is the same.
Cumulative Incremental Backup
Sunday: Level 0
Monday: Level 5
Tuesday: Level 5
Wednesday: Level 3
Thursday: Level 5
It is interpreted as: Full backup is performed on Sunday, and blocks that have changed since Sunday backup are backed up on Monday. for Tuesday, the last backup at the same level-1 or low level is Sunday (Level 5-1 is level 4 or lower), so we still back up blocks with changes after the backup on Sunday; wednesis Level 3, the last backup at the same level-1 or lower is level 0 on Sunday, so it is a backup of blocks that has changed since Sunday backup. On Thursday, we back up blocks after Wednesday backup, because Wednesday is Level 3, lower than Level 5-1. If you change Level 5 to level 2 and level 3 to level 1, the result is the same.

Author:Weishouqun Time:02-04-10 16:02

To the white dust
Consult
How to Write Level 3 scripts?
How can I make Level 3 based on level 0?
When performing Incremental backup, I found Level 3 prompts that the parent backup or copy of Data File 1 could not be found.
The generated backup file is large. It seems not level 3

Author:Weishouqun Time:02-04-10 16:13

My script is written in this way.
Create script level0bak
{Allocate channel D1 type disk;
Backup incremental level 0
Format 'd:/dbbak/A/DF % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}
Create script level1bak
{Allocate channel D1 type disk;
Backup incremental Level 1
Format 'd:/dbbak/A/DF % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}
When Level 1 is executed, the system prompts that the parent backup or copy of Data File 1 cannot be found.
No parent backup or copy of data file 2 found
.
.
.
In short, the parent backup or copy of all data files cannot be found.

Please kindly advise me

Author:Lunar2000 Time:02-04-11

Quote:

Initially released by weishouqun
My script is written in this way.
Create script level0bak
{Allocate channel D1 type disk;
Backup incremental level 0
Format 'd:/dbbak/A/DF % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}
Create script level1bak
{Allocate channel D1 type disk;
Backup incremental Level 1
Format 'd:/dbbak/A/DF % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}
When Level 1 is executed, the system prompts that the parent backup or copy of Data File 1 cannot be found.
No parent backup or copy of data file 2 found
.
.
.
In short, the parent backup or copy of all data files cannot be found.

Please kindly advise me

Let me try:
Create script level0bak
{Allocate channel D1 type disk;
Backup incremental level 0
Format 'd:/dbbak/A/df_full _ % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}

Create script level2bak
{Allocate channel D1 type disk;
Backup incremental Level 2
Format 'd:/dbbak/A/df_level2 _ % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}

Create script level1bak
{Allocate channel D1 type disk;
Backup incremental Level 1
Format 'd:/dbbak/A/df_level1 _ % S _ % P' filesperset 5
(Database include current controlfile );
Release channel D1;
}

Author:Snowhite2000 Time:02-04-12

You have always executed level 0 before Level 1. If you have not executed level 0, there is no way to execute Level 1, right?

Author:Lunar2000 Time:02-04-16

Bai Xue, It's not old, ah

Author:Snowhite2000 Time:02-04-16 :44

Welcome, welcome!

Author:Bellsz Time:02-05-13

There is a PDF on the Forum about rman, written by johnwuwuwu. It's good.