SAP High Availability and the Windows Environment
How does SAP support High Availability in Windows environments?
SAP provides an out of the box setup for windows cluster environments using the Microsoft Cluster Service (MSCS). For all other windows cluster solutions please get in touch with the specific cluster software vendor.
What is a cluster resource group?
Cluster resources are software and hardware components that are managed by the cluster software. Several resources can be grouped into resource groups. These groups are collections of resources which can be managed by the cluster service as a single unit.
Why can't I access the shared disks when they are part of another cluster node?
The shared disk always belongs to the cluster node that owns the cluster group at the moment. However, you should never access the SAP installation by choosing the disk drive but by using the shared name, that means "/sapmnt." This prevents the loss of the disk during sensitive operations like installations, etc.
How many failover nodes are currently supported by MSCS/SAP?
The number of SAP cluster nodes is only limited by the maximum of cluster nodes supported by MSCS. For Windows Server 2003 the maximum is 8 cluster nodes which mean 7 failover nodes. When using the SAP Replication Server with a cluster configuration the number of nodes is currently limited by two nodes.
How can I initiate a failover on MSCS manually?
On MSCS, failovers can be initiated for testing purposes manually. You can open a command prompt a type in “cluster res /FAILâ€