Recovery Models
The Recovery Model influences the way in which the SQL Server executes backups and determines to which degree a database can be restored after it has been damaged. It is therefore a crucial setting for a production database. For an SAP production system, the Recovery Model must be set to Full to enable the database to be optimally restored when it is damaged.
You can set three different types of recovery models for a database:
- Full Recovery Model
- Bulk-Logged Recovery Model
- Simple Recovery Model
When this model is set for the SAP database, it ensures that no work is lost when the database is damaged. It enables the database to be restored to the state it had before it was damaged using a full database backup and subsequent transaction logs. With the Full Recovery model all actions are fully logged.
Bulk_Logged Recovery Model
When this model is set, bulk copy operations are not logged. Nevertheless it is possible to restore the database to a state including the non-logged operations if a transaction log backup is performed after the bulk operation. With the bulk recovery model set, the transaction log backup also includes the database pages changed during the bulk operation. Note that this type of logging may result in very large transaction log backups.
When you use this model, you cannot perform a point-in-time restore of the transaction logs.
Simple Recovery Model
When this model is set, transaction logs are truncated when a checkpoint occurs to allow log space to be re-used. As a consequence no logs are available to restore a damaged database. With this model it is therefore possible to restore a database backup but not to apply any transaction log backups. All changes since the last database backup are lost.
Never enable the Simple Recovery Model for an SAP system.