SQL licensing for Lync

Which version of SQL server do I need ?

Normally, Microsoft SQL Express edition is the default database that ships with Lync.

For high availability reasons, sometimes a Microsoft SQL server cluster is necessary. For this, you'll need a Standard or Enterprise edition.

  • Microsoft SQL Express ( default )
  • Microsoft SQL Server 2008 Standard
  • Microsoft SQL Server 2008 Enterprise

SQL Standard or Enterprise ?

The choice depends on the number of windows failover clustering nodes you'll install. The Standard version supports clusters with up to 2 nodes and maximum 64 GB RAM. The Enterprise version is capable of addressing even more memory and supports huge clusters.

How many CAL's do I need ?

I assume that you've choosen for a SQL Server 2008 Standard cluster in this case.

  • Lync 2010 Standard
    • There is no need to buy CAL's
  • Lync 2010 Enterprise
    • The number of users that will use Lync



SQL edition HA CAL’s CPU licenses extra OS licenses SQL Server 2008 licenses

SQL Express






SQL Standard


0 / #users *



1 STD license ***

SQL Enterprise


0 **



+1 ENT license ***


* Lync Standard edition does not require any CAL's. Lync Enterprise does require CAL's.

** CAL's for an unlimited amount of users included.

 *** SQL server licenses needed for every active cluster node. Passive nodes don't need a license. After a failover, passive node can take over the load and run for 30 days without a license. In other words: You should failback to an active node within a timeframe of 30 days.

Related links

Licensing Guide for SQL Server 2008