What Needs to be Backed Up? (SAP Library - SAP/ MS SQL Server DBA in CCMS (BC-DB-MSS-DBA))

What Needs to be Backed Up?

Resources in your system that need to be protected from loss are the Windows NT configuration and objects, the data in the databases and the corresponding transaction log files.

The following subsection gives general recommendations for a backup strategy. Keep in mind that the frequency and type of backups required vary widely. You need to find a solution that best fits your environment.

Windows NT, R/3 and SQL Server Files

The entire system, including all Windows NT, R/3 and SQL Server files must be backed up regularly using the NT Backup utility. The backup of these files is necessary for a restore operation when the disk on which SQL Server and R/3 executables are located crashes. In addition, it serves as an additional backup that may play a vital role in dealing with emergency situations where other routine backups have been damaged.

Backup type: Full Windows NT backup.
Frequency: The windows NT, R/3 and SQL Server files need to be backed up:

After installing an NT or SQL Server Service pack
Before special actions such as an R/3 Upgrade or Client Copy

How to Perform: Use the Windows NT Backup tool. The database must be offline and the SQL Server shut down.

Use the auxiliary NT system to backup the files. For information on how to proceed, refer to the Windows NT documentation.

Never use Windows NT backup for regular database backups that are part of a predefined backup and restore strategy. NT database backups cannot be used to fully restore a database because the transaction logs cannot be applied. This means the changes made to the database after the last database backup cannot be redone. The database can therefore only be restored to the state it had at the time of the last NT backup and all the changes since the last database backup are lost.

Data of the R/3 and SQL Server databases

The data of the R/3, master, and msdb database must be backed up at regular intervals with database backups. These backups are essential to enable restore operations, if the database is damaged.

Backup type: Full database backup
Frequency: In general, the R/3 database <SAPSID> should be backed up once a day. It is sufficient to backup the master and msdb databases once a week or month, depending on the amount of database activity in your system. For administrative reasons, it is however easier to simply backup the master and msdb databases whenever you backup the R/3 data. This hardly has an impact on system throughput as these backups do not require much additional space or time.
How to perform: Use the CCMS Planning Calendar of the R/3 System for backups that are regularly scheduled. Use the SQL Server Enterprise Manager for exceptional backups that are not part of the normal backup routine.

See also:

Backing Up with R/3

Backing Up with the Enterprise Manager

R/3 Transaction Log

The transaction log of the R/3 database that records changes made to the database must be backed up separately.

Backup Type: Transaction log backup.
Frequency: SAP recommends that a transaction log backup be scheduled every 30 to 60 minutes on a normal work day. If your R/3 System(s) are used productively at weekends, schedule additional backups for weekends.

To work out the frequency of transaction log backups, also take the fill rate of the log into account. This depends on the size of the transaction log and the transaction rate on your system. Whenever a transaction log is backed up, it is truncated. This means old entries are deleted so that enough space is available for new entries. Consequently, if the log is not dumped frequently enough, it will grow until the disk is full and no more changes to the R/3 database are possible.

When the disk system containing the transaction log crashes, it is impossible to backup the log that was in use at the time of crash. However, a backup of this log is necessary to restore the database to the state it had prior to the failure. It is only possible to return the database to the state it had at the time of the last transaction log backup. For this reason, SAP strongly recommends very frequent transaction log backups (every 30 to 60 minutes).

How to perform: Use the Planning Calendar in the R/3 System, or alternatively, the SQL Server Enterprise Manager.

See also:

Backing Up with R/3

Backing Up with the Enterprise Manager