Lync Server 2013 supports the user of either SQL mirroring or SQL clustering for each Lync Server database. You can easily set up SQL mirroring with the Topology Builder tool in Lync Server 2013. For SQL failover clustering, you must use SQL Server for setup.
Lync Server 2013 supports SQL clustering topologies for all deployments, including greenfield deployments and organizations that have upgraded from previous versions of Lync Server.