Log backups complement the data backups and enable the status of the database instance at any point in time. Without log backups, you can only restore the status of the database instance up to the time of the last data backup.
During a log backup, the log area of the database instance is written to version files or backed up using an external backup tool.
It is backed up in backup units, called log segments. If you are using version files, a version file is created for each log segment of the log area. After the backup, the part of the log area that was backed up is released again for overwriting.
You can activate the automatic log backup or perform interactive log backups.
We recommend automatic log backups in particular for database instances in which many changes are made to the data and therefore a great number of log entries can be expected. If automatic log backup is activated, you do not have to monitor constantly how full the log area is.
Types of log backup
Name |
Description |
Automatic log backup |
Log segments of the log area are automatically backed up as soon as they are written and are then released again to be overwritten. This mechanism practically prevents the log area from overflowing. |
Interactive log backup |
With an interactive log backup, you use the Database Manager to back up all pages of the log area that have been written since the last log backup. If you back up the log entries in version files, then a version file is created for the last log segment that may not have been filled. |
· When the automatic log backup is switched on, you cannot start an interactive log backup; you can perform a data backup at the same time, however. You cannot perform any other backup as long as an interactive log backup is running.
· Automatic log backups are made in ONLINE operational state only. Interactive log backups can be performed in operational states ONLINE or ADMIN.
· To be able to perform an interactive log backup, a complete data backup of the current database instance has to have been done once already.
You are using the Database Manager database tool or the CCMS in SAP systems to create log backups.
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1. Create a backup medium.
Only version files are permitted for automatic log backups.
2. Activate the automatic log backup with the corresponding log setting, or perform an interactive log backup.
Automatic log backup:
¡ Database Manager GUI, Activating or Deactivating the Automatic Log Backup
¡ Database manager CLI, Activating the Automatic Log Backup
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Database Administration in CCMS: MySQL
MaxDB, Activating Automatic
Log Backup
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Database Administration in CCMS: SAP
liveCache, Backing Up
liveCache
Interactive log backup:
¡ Database Manager GUI, Backup Procedures
¡ Database Manager CLI, Commands for Backing Up and Archiving
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Database Administration in CCMS: MySQL
MaxDB, DBA Planning
Calendar
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Database Administration in CCMS: SAP
liveCache, Backing Up
liveCache
3. If you are using version files as the backup medium, archive these version files regularly to an external backup medium using operating system commands or the Database Manager CLI (see Archiving the Version Files of the Log Area).