Three common mistakes in Oracle Database Backup

The following describes common mistakes and common problems of Oracle Database Backup for your reference. If you have any problems with Oracle database backup, take a look.

Common Mistakes in Oracle Database Backup:

1. Use EXP/IMP for backup

EXP/IMP is not a good backup tool. In the future development, ORACLE will have lower and lower support for EXP/IMP backup. ORACLE only regards EXP/IMP as a good tool rather than a backup tool. For large databases, such as TB-level databases or data warehouses, EXP/IMP will certainly be insufficient.

2. Back up the database in the Application

There are many such requirements on the Forum: "How can I back up and restore the Oracle database in a program ?". First of all, this is not impossible, but the implementation process will be complicated and unexpected. As far as my feelings are concerned, the first point of the question is that I don't know about ORACLE or DBA. If ORACLE can easily implement backup and recovery, I can say, no DBA is required.

3. Cold backup is easier than hot backup, and the effect will be better

Some people think that cold backup is to close the database for consistent backup, it is certainly better than the specific heat backup, it is easy to use, in fact not all, in hot backup, the same can achieve full backup of the database, it does not affect the operation of the database. It is recommended that all production machines run in archive mode and adopt hot backup mode.

FAQs about Oracle Database Backup:

1. Why can't I import the exported data and prompt unsupported Character Set conversion?
A: refer to the character set principles above. When exporting data, the client is consistent with the database character set. When importing data, change it to the same as the target database character set.

2. I have more and more archived logs. When can I delete archived logs?
A: each full backup, such as OS full cold backup or full hot backup) or Incremental Backup Based on full backup, such as RMAN Incremental Backup Based on level 0 backup) you can delete the archived logs before the backup point. We recommend that you keep the logs on the tape for one year.

3. Must all data files be backed up during full backup?
A: No. There are at least two types of data files that can not be backed up. One is temporary data files. If they are lost, they can be deleted and rebuilt. The other is read-only tablespace data files, if the read-only attribute of the tablespace has not been modified since the last backup, backup is not required.

4. Do I need to back up online logs?
A: For archive hot backup, there is no need to back up online logs. However, for cold backup, you can back up online logs, especially those that are not archived. The cold backup after the online log is backed up. Because the database is consistent, it can be restored to this backup point.

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