VMware High Availability (HA) has helped our SAP customers achieve their uptime requirements and meet their target SLAs. VMware vSphere 4 introduces VMware Fault Tolerance (FT), a feature that allows a virtual machine to continue running even when the underlying physical server fails. It is a software solution that runs on commodity hardware and does not require any modifications to the guest operating system or SAP applications running inside the virtual machine. This new FT feature can provide further protection to SAP single points of failure with zero downtime. An ideal candidate for this feature is the lightweight central services component – SAP enqueue can be protected in the event of hardware failure with no loss of locks without the complexity of configuring replicated enqueue and clustering.
VMware FT and VMware HA satisfy the requirements of different HA scenarios for SAP customers. These scenarios, along with third party clustering solutions certified on VMware such as Microsoft Cluster System, are described in the paper "SAP Solutions on VMware: High Availability" which can be found here.
The paper describes and compares the different scenarios to help our customers architect highly available SAP solutions in a VMware virtualized environment.
-Vas Mitra