Database backup and Rman backup

1. Full database backup: Divided into archive and non-archive by archive mode

Archive mode

Open state, non-consistent backup

Off state, can be divided into consistency and non-conformance

Non-archive mode

Open, non-consistent backup invalid

Shutdown status, consistent backup, non-consistent backup not recommended

2.RMAN Backup

Rman uses a server session to complete the backup operation, and connecting to the server from the Rman client will result in a server session

Rman Backup includes: The entire database, table space, data files, specified data files, control files, archive log files, parameter files, etc.

Type of 3.RMAN backup

Full or incremental backups (incremental)

Consistent backup (consistent) or inconsistency backup (inconsistent)

Hot Spare (open) or cold standby (closed), the database must be in a mount state when Lengbei, and cold standby can be either a consistent or a non-consistent backup

Full backup

A complete copy of one or more data files that contains all the blocks of data from the beginning of the backup. Full backups cannot be the basis for incremental

Incremental backups

Contains blocks of data that have been modified or added since the most recent backup. Can be divided into differential incremental and cumulative incremental backups

A differential incremental backup contains only the modified block of data below n or N levels. Small amount of backup data, long recovery time.

A cumulative incremental backup contains only the modified blocks of data below the n-1 level or n-1 level. Large amount of backup data, short recovery time.

A level 0 incremental backup is equivalent to a full backup that contains all the used block files, and the difference to a full backup is the basis for a full backup that cannot be used as a level incremental backup

Consistent backup

All modifications in the files contained in the backup have the same system change number (the systems changes NUMBER,SCN).

That is, all the data in each file contained in the backup comes from the same point in time.

After a consistent database full backup (consis-tent whole database backup) is restored (restore), no recovery action is required (recovery)

Non-consistent backup

After the database is open (open), or the database closes abnormally (shut down abnormally), one or more data

A backup of the library file. Non-conformance backups need to be restored after the restore operation

4. Backup sets and mirrored replicas

Backup sets

is a collection of binaries that contain one or more data files and archive log files. Backup sets consist of backup slices, one backup set can contain one or more backup slices

You can set the number of backup slices that can be contained in the backup sets by using the Filesperset parameter.

You can also set the parameter maxpiecesize to set the size of each backup slice.

The spare block of data in the backup set will not be backed up, so the backup set can support compression. Backup sets support incremental backups and can be backed up to disk or tape.

Mirrored copy

is a full copy of the data file or archive log file, and cannot be backed up to tape or incremental backup without any compression, etc.

Immediate recovery can be used immediately upon recovery

Replication commands equivalent to the operating system

Can be a level incremental backup

5. Backup path

Can be backed up to a disk directory

Can be backed up to tape

Flash Back Zone

6. Backup Limits

Database must be in mount or open state

Cannot back up online logs

Only clean backups in non-archive mode, i.e. backup at clean shutdown and boot to mount state

In archive mode, data files can be backed up in current state