Best Practices SQL Server 2005 High Availability

[Former Member]

The recommended high availability architecture is to have SQL Server and the SAP Central Instance reside on the same cluster. We would like to move the SAP Central Instance off the database layer to an active\active cluster in the application layer. Has anyone had any experience with this? or does anyone see any problems with this proposed architectural change?

[Former Member]

First of all what Central Instance you are talking about - the classic one only containing the ABAP Central Instance or the Netweaver 2004S one (ABAP Central Services)?

should not really be a problem since in the non cluster environment the configuration of standalone database nodes are supported.

since a pure database cluster is nothing else then a standalone database host (accessed via a virtual database hostname).

If you are doing something like homogenious system copy - should be no problem.

If you intend to separate a CI (classic or new style) from an existing cluster to a new one - well there is no procedure defined for this at the moment.

peter

[Former Member]

Hi Logan,

Where do you find the recommendation?

SAP's recommendation is to have the Central Instance (ASCS/SCS) in one switchover group and the database in another switchover group. For example, there is no need to be switching over the database to another host just because the message or enqueue has died...

Best Regards,

Matt

[Former Member]

Hi Matt,

I appreciate the rapid response.

This is the document I was referencing. If there is a more up to date architectural recommendation I would greatly appreciate it. Do you know were I can find the most recent recommendations andor best practices?

https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/4ab89e84-0d01-0010-cda2-82ddc354...

Thank You,

Logan

[Former Member]

Hi Logan,

I am having trouble accessing the link above...it says the file is corrupt. Can you give me the navigation to it? Thanks.

Best Regards,

Matt

[Former Member]

Hi Logan,

I finally found the document and was able to download it ;-)...

I have not read the entire document, but I found the same recommendation on page 7:

A typical Microsoft clustering scenario includes running the SAP Central Instance (CI) on one of the cluster nodes and SQL Server 2005 on the other cluster node. In this case, if the primary node for SQL Server 2005 or for the SAP CI fails, or if that node is taken offline for maintenance, the clustered components will start on the active cluster node without a service interruption.

You may also find more HA information on the SAP Service Marketplace at http://service.sap.com/ha. Navigate to Media Library -> Documentation -> Switchover -> SAP WebAS in Switchover Environments (6.40).

Best Regards,

Matt