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This article mainly shows you the "Oracle database backup and recovery example analysis", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and study the "Oracle database backup and recovery example analysis" this article.

In today's information-based data age, data has become the most valuable and valuable thing for the government and enterprises and institutions, and the most valuable data is mainly stored in the database, so for IT management or database maintenance personnel, data backup is the top priority of the IT department.

In the whole database market, Oracle accounts for about 48 per cent of the world database market share, while Oracle occupies about 57 per cent of China's database market share. Therefore, it can be said that in the process of Oracle database maintenance, Oracle database backup and recovery is also a top priority. Although there are many times when the database system runs slowly, for the data loss of the database, it is obvious that the loss of data loss is *, and it is also the life value of an enterprise. Below, Brother Feng will talk about the understanding and experience of Oracle database backup and recovery.

Physical backup and logical backup

Data is a copy of data, which can be used to rebuild the database. Backup can be divided into physical backup and logical backup:

1. Physical backup: a copy of all physical files, such as data files, log files, control files, archive files, etc., which are stored on local disk or corresponding storage. Physical backup includes cold backup (non-archive mode) or hot backup (archive mode).

two。 Logical backup: tables, indexes, stored procedures, etc., can be exported using binaries derived from oracler exp/expdp, and then imported into the database through Oracle's imp/impdp. It can be said that logical backup is a supplement to physical backup, which is generally used for data migration.

II. Tools for backup and recovery

1. Commonly used is to use oracle rman to backup and restore, support command line and graphics interface, can be backed up through third-party software (NBU\ LEGATO\ TSM, etc.) and tape drive, this tool is very powerful; RMAN supports backing up entire databases, tablespaces, data files, control files, and archived log files, etc., and can achieve fast backup operations through RMAN scripts RMAN supports incremental backups, skips partial block backups, and adjusts the speed of backups; and it can detect some corrupted databases during backups, and improve backup performance through multi-channel concurrency, limiting the speed of IO, the number of files in a single backup, and so on.

two。 In fact, IMP/IMPDP and EXP/EXPDP are used for logical backup and recovery, which can be migrated across platforms and support full-database, user and table-level backup and recovery. Especially after Oracle 10g, EXPDP and IMPDP backups are relatively fast and support multiple concurrency.

3. Oracle datagurad, oracle goldengate and other products can be used to achieve database disaster recovery backup, data replication and post-disaster recovery.

4. Third-party tools, you can use operating system commands, you can also use tools such as sqlplus,dul,bbed to achieve backup and recovery in some special cases.

III. Backup and recovery on database configuration

1. Control file multiplexing

two。 Mirror image of online redo log

3. The same archive can be backed up to multiple locations in archive mode

Mirroring of 4.ASM data files and disk groups

5. Mirror configuration of data files using operating system and storage

Configuration of 6.ORACLE RAC configuration information

7. Mirroring data files using hardware technology

IV. Several important files in Oracle backup and recovery

1. Data file

two。 Control file

3. Redo online log files

4. Parameter file

5. Archive log file

Introduction of Oracle backup

1. Full backup and incremental backup (differential increment and cumulative increment)

Full backup: a complete copy of one or more data files, including blocks at all levels from the start of the backup.

Incremental backup: contains blocks that have been modified or added since the most recent backup. Incremental backup is divided into 0-level incremental backup, 1-level differential incremental backup and 1-level cumulative incremental backup. Incremental backup supports archived and non-archived modes, and incremental backup can only be realized when RMAN is used.

Differential increment: all the data blocks that have changed since the backup parent and peer backup, and the differential increment is the default incremental backup method.

Cumulative increment: is the block of data that has changed since the backup parent backup.

two。 Full backup and incomplete backup

Full backup: including all data files, control files, parameter files, password files, online redo log files, archive log files.

Incomplete backups, such as backing up one or more data files, one or more tablespaces, etc., are valid only in archive mode.

3. Offline backup and online backup

Offline backup: the backup occurs when the database is closed, also known as cold backup. After the database is shut down consistently, the SCN of the control file is consistent with the SCN of the header of the data file.

Online backup: a backup that occurs when the database is in use, also known as inconsistent backup or hot backup. The SCN of an online backup of a data file is inconsistent with the control file. An online backup can be a full or partial backup and can only be completed in archive mode.

VI. Introduction to Oracle recovery

The database recovery strategy is to use the most recent backup to restore the database, and then use archive logs and online logs to restore the database to a * or specific state.

Oracle recovery is mainly divided into restore and recovery.

Restore: the process of finding what you need from the most recent backup file and copying it back to its original location is called restore. You can restore basic databases, table spaces, data files, control files, and parameter files.

Restore: on the basis of restore, use archived log files and online log files to refresh the database to the SCN of * to keep the database consistent.

Recovery: recovery by instance, crash recovery, media recovery.

Instance recovery: in a RAC environment, when an instance crashes, available instances automatically use online logs to roll forward committed transactions, undo uncommitted transactions, and release locks. There are three main stages of instance recovery (instance recovery): using redo log files cache recovery, open database, and using undo for transaction recovery.

Crash recovery: in a single-instance or multi-instance environment, if all instances crash, in crash recovery, the instance needs to open the database and then perform a restore operation. Crash recovery (Crash Recovery) this is done automatically by Oracle without manual intervention.

Media recovery: media recovery can restore the entire database, a data file, a tablespace file, or a log file to a specified point in time; media recovery (Media Recovery) can be divided into complete recovery or incomplete recovery, RMAN supports full media recovery and incomplete media recovery, the basic commands used by RMAN are restore and recover.

The above is all the contents of the article "sample Analysis of Oracle Database backup and recovery". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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