Solution from HP
Source: http://h20195.www2.hp.com/V2/GetPDF.aspx/4AA1-4068ENW.pdf
HP recommends this 2-server solution for SMB customers who are looking to deploy solutions in a virtualized environment using Microsoft Hyper-V R2, and also wish to employ high-availability technologies to ensure continuity of service. The expected user population is up to 150 users (assuming an active user concurrency of typically 30-50%).
It uses the same SharePoint service deployment topology as the “Medium-sized configuration (3-server solution)” physical server solution, but deploys the three roles onto three virtual machines (VMs) rather than three physical servers. The two servers are formed into an active/active failover cluster and then run Hyper-V R2 to virtualize the environment. The three roles are then deployed onto three VMs across the cluster, each VM being configured with 4 virtual CPUs (cores) and appropriate memory.
The total server memory has been sized to support the VMs and any Hypervisor and OS overhead. Nominally the SharePoint WFE and Query Search roles would run on Server “A”; and the Index Search and SQL roles on Server “B”. However should a server fail for some reason, the solution has been sized such that the remaining active server can support the full required load and role VMs will automatically fail-over to the running server. Storage utilizes an HP P2000 G3 MSA to provide the required SAN technology to support the failover cluster. An AMD-based solution is shown.