{"id":184,"date":"2013-04-02T13:49:03","date_gmt":"2013-04-02T13:49:03","guid":{"rendered":"http:\/\/blog.lync2013.org\/?p=86"},"modified":"2014-05-06T09:15:17","modified_gmt":"2014-05-06T09:15:17","slug":"lync-2013-high-availability","status":"publish","type":"post","link":"https:\/\/modern-workplace.uk\/?p=184","title":{"rendered":"Lync 2013 High Availability"},"content":{"rendered":"

*Review updated on April\u00a017, 2014<\/span><\/p>\n

High availability is something that companies do not take for granted, they take it as given (especially when we talk about telephony). While Lync 2010 did a good work on this critical aspect there were still some weak points on the architecture when there was the need for a really continuous service. For example the mechanism behind the \u201cbackup registrar\u201d implementation was really a limit and, for the Enterprise Front End deployments, the need for a clustered SQL server Back End was a restriction and did not match with the requirements related (also) to some kind of disaster recovery plan.<\/span><\/p>\n

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Front End Pairing and new rules on licensing<\/h4>\n

Lync 2013 makes a step forward, building on what was valid in the previous logics and using whole new solutions were they are necessary. The first huge improvement is related to the so called \u201cFront End pairing\u201d. I have created a presentation about this solution some time ago (http:\/\/bit.ly\/XKCBzd) anyway what you need to know is that now your Standard Edition Front Ends (or your Enterprise Edition pools) can be tied and you are able to failover and failback users completely from one Front End to the other one with a simple Shell command. Some limits apply (pairing is supported only on similar Front Ends, so Enterprise Edition and Standard Edition mixes are not supported) but the result is really what you wish you had some years ago. The licensing has changed accordingly so that now there is no difference in the costs of a Standard or Enterprise edition of Lync. Obviously we are not talking about a \u201cfree lunch\u201d because an Enterprise Edition deployment has a suggested minimum of three servers and you have to add the cost of at least one SQL server license to the amount. Talking about the Lync databases, we have another hot topic<\/span><\/p>\n

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Back End mirroring<\/span><\/h4>\n

The Lync Back End server (basically a SQL database hosting some of the Lync configurations and data) is really less important than it was in the past (and that\u2019s why we are able to pair the Front Ends) but it is still mandatory for an Enterprise configuration of Lync. The high availability for Lync 2013 Back End supports:<\/span><\/p>\n