In the first post of this series I highlighted that with Windows Server 2016 there are some feature differences between the Standard and the Enterprise Editions that might get lost in some of the messaging, so in this series of posts I’m going to be highlighting the feature set of Windows Server 2016 Standard, and will include information from a few different resources, but the primary one is the Windows Server 2016 Technical Preview 5 Feature Comparison. As mentioned in the first post of the series, these will focus on what’s new from a Windows Server 2012 R2 perspective, rather than Windows Server 2008 R2 or Windows Server 2012 perspective. I will focus on those later if needed.
Following on from the previous post in the series, which was on Virtualisation, today’s topic is High Availability, and following you will find the information from the Feature Comparison Guide.
Please note that these are subject to change and are based on Windows Server 2016 Technical Preview 5. If any adjustments need to be made, please leave a comment.
Microsoft continues to invest in enhancing and improving the high availability capabilities provided by Windows Server Failover Clustering. In Windows Server 2016, new and improved features simplify your ability to deploy and manage highly available failover clusters.
Cluster Infrastructure Requirements
Cluster Rolling Upgrade
Cluster OS Rolling Upgrade is a new feature in Windows Server 2016 that enables an administrator to seamlessly upgrade the operating system of nodes in a Failover Cluster from Windows Server 2012 R2 to Windows Server 2016. When a rolling upgrade of a cluster takes place, there will be a temporary mixture of Windows Server 2012 R2 hosts and Windows Server 2016 hosts. Using this feature, the downtime penalties against Service Level Agreements (SLA) can be avoided for Hyper-V or the Scale-Out File Server workloads.
Cloud Witness enables using Azure blob storage as a witness in quorum for a stretched cluster. Cluster witness can now be a Disk Witness, File Share Witness, or Cloud Witness. This feature allows customers to use Azure as a third datacenter hosting the Cloud Witness, without the setup and maintenance overhead associated with running a File Share Witness on a File Server VM in Azure
Active Directory-independent clusters
Active Directory-independent clusters provide the ability to deploy a failover cluster with less dependency on Active Directory Domain Services. With Windows Server 2012 R2 the Active Directory-detached clusters feature allows having clusters with names not attached to AD. With Windows Server 2016 Failover Clusters can be deployed in workgroups and multiple domains.
Windows Server 2016 Cluster Resiliency features
Windows Server 2016 introduces new features to improve cluster resiliency.
- Cluster Quarantine: Prevents flapping nodes from negatively impacting other nodes and the overall cluster health. Unhealthy nodes are prevented from joining the cluster for a time period. Once quarantined, VMs hosted by the node are gracefully drained to healthy nodes.
- Site Awareness: Fault domains with failure and placement policies which are aware and optimized for the physical locations of stretched clusters across sites. Enhances key operations during the cluster lifecycle such as failover behavior, placement policies, heartbeating between the nodes and quorum behavior.
- Node Fairness: Identifies idle nodes in a cluster and distributes virtual machines to utilize them, to dynamically load balance the cluster.
Cluster node health detection
Cluster node health detection increases the resiliency to temporary network failures for virtual machines that are running on a Hyper-V cluster.
CSV Cache provides a write-through cache for unbuffered IO, which significantly boosts virtual machine performance. Scalability improvements to increase the amount of memory that can be allocated as CSV Cache.
The CSV Cache with Windows Server 2016 also has interoperability enhancements, such as being compatible with Tiered Storage Spaces and Deduplication.
Adds CSV support for the following Windows Server features:
- Resilient File System (ReFS).
- Parity storage spaces.
- Tiered storage spaces.
- Storage Spaces write-back caching.