Topic Last Modified: 2011-05-15

The solution described in this section assumes that your Lync Server deployment meets both the core requirements described in the product documentation and all of the following prerequisites. To qualify for Microsoft support, your failover solution must meet all these prerequisites.

• All servers that are part of geographically dispersed clusters must be part of the same stretched VLAN, using the same Layer-2 broadcast domain. All other internal servers running Lync Server server roles can be on a subnet within that server’s local data center.
  
  Edge Servers must be in the perimeter network, and should be on a different subnet than the internal servers. Also, the perimeter network need not be stretched between sites.
  
  
• Synchronous data replication must be enabled between the primary and secondary sites, and the vendor solution that you employ must be supported by Microsoft.
  
  
• Round-trip latency between the two sites must not be greater than 20 ms.
  
  
• Available bandwidth between the sites must be at least 1 Gbps.
  
  
• A geographically dispersed cluster solution based on Windows Server 2008 R2 Failover Clustering must be in place. That solution must be certified and supported by Microsoft, and it must pass cluster validation as described in the Windows Server 2008 R2 documentation. For details, see the “What is cluster validation?” section of “Failover Cluster Step-by-Step Guide: Validating Hardware for a Failover Cluster” at http://go.microsoft.com/fwlink/?linkid=142436.
  
  
• All geographically dispersed cluster servers must be running the 64-bit edition of Windows Server 2008 R2.
  
  
• All your servers that are running Lync Server must run the Lync Server 2010 version.
  
  
• All database servers must be running the 64-bit edition of one of the following:
  
  
  • Microsoft SQL Server 2008 with Service Pack 1 (SP1) (required) or latest service pack (recommended)
    
    
  • Microsoft SQL Server 2008 R2
    
    
• Both physical and virtual servers are supported. For details about running Lync Server 2010 on virtual servers, see Running in a Virtualized Environment.