Replication and High Availability
A database can fail due to hardware or logical errors. To restore the database, data and log backups must be imported. If you need to import a lot of data, restoring can take quite a long time. During this time, the database is not available for users.
To make the database available for users more quickly (high availability), you can choose between several replication methods.
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A snapshot stores the state of the data area at the time of the snapshot. A snapshot is not a replication mechanism and not a data backup, but you can return to the state of the data area at the time of the snapshot. |
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You copy the active database. A database copy is not a replication mechanism, but is required for setting up other replication mechanisms, such as standby databases. |
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You update a duplicate of the active database asynchronously. You copy the log backups of the original database to the standby database computer and import them into the standby database. When the original database fails, you can quickly resume operations with the standby database after importing the most recent redo log entries. |
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Depending on the chosen solution, one or multiple duplicates (standby databases) of the active database (master database) ensure that the downtime after a system failure is reduced to a minimum. As soon as the master database fails, a standby database can take over operation. |
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SAP Note 952783
