Topic Last Modified: 2012-09-25
Lync Server 2013 provides high availability by server redundancy via pooling. If a server running a certain server role fails, the other servers in the pool running the same role take the load of that server. This applies to Front End Servers, Edge Servers, Mediation Servers, and Directors. For details about server roles, see Server roles.
Lync Server 2013 also provides disaster recovery measures by enabling pool pairing. If you deploy this topology, you will designate pairs of Front End pools, with each pool in a pair located in a separate data center, and in a separate geographical area. If one pool or site goes down, you can redirect the users of that pool to use the other pool in the pair, with minimal interruption of service.
Lync Server 2013 also supports Back End Server high availability. This is an optional topology in which you deploy two Back End Servers for a Front End pool, and set up synchronous SQL Server mirroring for all the Lync databases running on the Back End Servers.
For details about pool pairing and Back End Server mirroring, see Planning for high availability and disaster recovery.