Tag: Windows Server 2012 R2

VLAN, Trunk, NIC Teaming, Virtual Switch Configuration in Hyper-v Server

If you checked my posts before and especially LAB scenarios maybe you noticed I didn’t tag VLANs and reason is I didn’t want to complicate things and I know that some people have problem with understanding how it all works in comparison with physical switches and all. This post is meant to help clear that and I hope it will help in better understanding of Hyper-V Virtual Switch.

Network virtualization provides multiple virtual network infrastructures run on the same physical network with or without overlapping IP addresses. Each virtual network infrastructure operates as if they are the only virtual network running on the shared network infrastructure. Hyper-v Network Virtualization also decouples physical network from virtual network.

How to create a Hyper-V VM template

In this post I will look at creating a virtual machine (VM) template that you can use to quickly deploy new VM’s from, without having to install and patch them each time.

It is particularly useful if you are in a small Hyper-V environment and don’t have System Center Virtual Machine Manager (VMM).

The beauty of using a template for VM deployment is standardization. You deploy a known configuration which can be pre-patched which reduces time during the post deployment tasks.

Failover Cluster Quorum

This topic aims to explain the Quorum configuration in a Failover Clustering.

What’s a Failover Cluster Quorum

A Failover Cluster Quorum configuration specifies the number of failures that a cluster can support in order to keep working. Once the threshold limit is reached, the cluster stops working. The most common failures in a cluster are nodes that stop working or nodes that can’t communicate anymore.

Imagine that quorum doesn’t exist and you have two-nodes cluster. Now there is a network problem and the two nodes can’t communicate. If there is no Quorum, what prevents both nodes to operate independently and take disks ownership on each side? This situation is called Split-Brain. Quorum exists to avoid Split-Brain and prevents corruption on disks.

The Quorum is based on a voting algorithm. Each node in the cluster has a vote. The cluster keeps working while more than half of the voters are online. This is the quorum (or the majority of votes). When there are too many of failures and not enough online voters to constitute a quorum, the cluster stop working.

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