Windows Server 2012 R2 Failover Cluster – Global Update Manager

Pretty interesting new feature is implemented in Windows Server 2012 R2 failover clustering that allows you to manage how cluster database is updated.

Service responsible for this is called Global Update Manager. This service is responsible for updating the cluster database. In Windows Server 2012, you were not able to configure how these updates work, but in Windows Server 2012 R2 it is possible that you  configure the mode of work for Global Update Manager.

Each time the state of cluster changes (for example, when cluster resource is offline) all nodes in the cluster must receive notification about the event, before the change is committed to the cluster database, by Global Update Manager.

In Windows Server 2012, Global Update Manager works in Majority (read and write) mode. In this mode, when change happens to the cluster, majority of cluster nodes must receive and process the update before it is committed to the database. When cluster node wants to read the database, cluster compares the latest timestamp from a majority of the running nodes, and uses the data with the latest timestamp.

In Windows Server 2012 R2, Global Update Manager can also work in All (write) and Local (read) mode. When working in this mode, all nodes in the cluster must receive and process the update before it is committed to the database. However, when the database read request is received, the cluster will read the data from the database copy stored locally. Since all roles received and processed the update, local cluster database copy can be considered as a relevant source of information.

Windows Server 2012 R2 also supports the third mode for Global Update Manager. This mode is Majority (write) and Local (read). In this mode majority of cluster nodes must receive and process the update before it is committed to the database. When the database read request is received, the cluster will read the data from the database copy stored locally.

In Windows Server 2012 R2, default setting for Hyper-V failover clusters is Majority (read and write). All other workloads in the clusters use All (write) and Local (read) mode. Majority (write) and Local (read) is not used by default for any workload.

Author: ddamir

Damir Dizdarevic is a b.sc.math and IT professional. He works as a manager of MS CPLS Learning Center in Logosoft Sarajevo, and as a lecturer and author of MOC courses. Occasionally, he also works as a system designer for complex enterprise environments. He is a founding member and president of Bosnian Microsoft Community. He has been working with Microsoft platforms for the last 17 years and he is particularly specialized in Windows Server, Exchange Server, mobility and virtualization. Microsoft awarded him with the Most Valuable Professional – MVP status for his outstanding contribution in sharing knowledge about Microsoft Server products, large number of lectures he delivered, and for his high technical competence. Damir owns several technical certificates (MCSE, MCTS, MCITP, and MCT) for Windows Server 2012, 2008 R2, Exchange Server 2010, Security and Hyper-V. He is regular presenter on conferences in ex-Yu region. On Microsoft Sinergija conference, for previous 7 years, each time he was graded as one of top three speakers. On a Bosnian MS conference, he is the best speaker for last two years. He is also a regular and highly graded presenter on other Microsoft conferences in region such as NT Conference (Slovenia), Microsoft Vizija (Macedonia), Microsoft Windays (Croatia), MS Technet, Mobility Day, KulenDayz etc. Damir is one of very few trainers in Europe who works as an author and reviewer of official MOC courses. In previous year, he was authoring courses 20417 (Upgrading Skills to Windows Server 2012), 20414 (Implementing an Advanced Server Infrastructure), 20412( Configuring Advanced Windows Server 2012 Services) and 20410 (Installing and Configuring Windows Server 2012). Also, he was authoring System Center 2012 courses and currently he is working on Exchange Server 2013 and Windows Server 2012 R2 courses. In addition, he has been working for 16 years now as one of the editors of BiH IT magazine INFO, where he published more than 300 technical articles, and he is also writing for the famous Windows ITPro Magazine (some of his work can be found at: http://windowsitpro.com/author/damir-dizdarevic).

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