Windows Fabric plays a key role for Front End pool services availability in Lync Server 2013 and Skype for Business Server 2015. In Lync Server 2010 this responsibility was managed by Cluster Manager. Lync Server 2013 / Skype for Business 2015 Front End Pool services availability totally depend on windows Fabric and Fault & Upgrade domains provisioned by the Topology Builder.
Lync Server 2013 and Skype for Business Server 2015 use brick model which is based on Windows Fabric and use lazy writes to update Back End Server databases. Windows Fabric is a distributed system platform for building scalable applications. It is used for both on premise and cloud scenarios. Windows fabric starts independently without any specific external configuration store. It has self-healing and decentralized features which provides self-monitoring and automatically adjustment (load balancing) without any single point of failure. Windows Fabric Hosts service (FabricHostSvc) is installed as part of “Setup and Remove Lync Server components. Windows fabric also elect primary, secondary and backup secondary (tertiary) replica, maintain replication between primary and secondary replicas. You can find config file on each server located at “C:\ProgramData\Windows fabric\<ServerFQDN>\Fabric\ClusterMainfest.current.xml”.
Below are the core services which use Windows Fabric:
- Routing Services
- Lync Storage Services
- MCU Factory Services
- Conferencing Data Services
Windows Fabric is nothing but works like Windows Server Cluster. Similar to Cluster, Windows Server works on Majority where every Front End Server serves as voters. To get the majority for Front End pool, it always calculate N/2 + 1 for even FE nodes & N+1/2 for Odd FE nodes.
There are two major concepts which rely on fault and upgrade domain. Fault domain basically correlates underlying hardware and widely considered at the time of virtualization where organizations or administrators place more than one similar server role on same host. While Upgrade domains correlates logical set of nodes for planning upgrades.
Part II covers quorum loss modes, server placement, SQL server requirement for majority and best practices.