Backup approach for SAP on SQL Server

[Former Member]

Hi,

My customer likes to confirm backup approach for his SAP environment running on SQL Server.

He is going to use EMC Replication Manager to quiesce SQL server (enter online backup mode) and then take storage snapshot and then backup to tape.

His question is:

Replication Manager supports running some pre-script before quiesce SQL database. Does he need to do some scripting in SAP level to coordinate quiesce of SQL database? He doesn't know what should be in the script.

Someone told him that it's just fine to just quiesce SQL and backup. There is no need to do anything in SAP side for this online backup.

Thanks and Regards

[clas_hortien]

Hi,

for me it is not totally clear, what you mean with 'quiesce the SQL Server'.

There is a command that can be issued via a special API to the SQL Server, which will freeze the SQL Server, means the SQL Server stops every IO. Then the storage snapshot takes places and later the SQL Server is thawn again via the same API. In the SQL Server Errorlog you will see entries like :

2002-06-03 05:54:27.61 spid340 Database P01: IO is frozen for snapshot

2002-06-03 05:54:33.30 spid340 Database P01: IO is thawed

This is a supported way to create a backup, but the functionality has to be implemented by the Backup Vendor. All major Backup Vendors are supporting this procedure in the meantime and have tools for this.

There is no need to do anything on the SAP side to prepare such a Freeze and Thawn. The incoming and outcoing traffic to/from the SAP system is hold as long the backup takes place. Later the normal operation is resumed so that the SAP works as before.

Regards

Clas

[Former Member]

His concern may be the checkpoints. We have a similar setup and we do not run any pre scripts. We put a lot of thought into it and concluded that quiescing the database would be good enough.

However for our DR/HA purposes we are going to copy some files to SAN in a pre script.

RSB