Tech Tips, Tricks & Trivia

Architecture diagram source:  Running Windows VMs for an N-tier architecture on Azure Elements of the architecture diagram: - Availability sets. Create an availability set for each tier, and provision at least two VMs in each tier. This is required to reach the availability SLA for VMs. - Subnets. Create a separate subnet for each tier. Specify the address range and subnet mask using CIDR notation. - Load balancers. Use an Internet-facing load balancer to distribute incoming Internet traffic to the web tier, and an internal load balancer to distribute network traffic from the web tier to the business tier. - Jumpbox. Also called a bastion host. A secure VM on the network that administrators use to connect to the other VMs. The jumpbox has an NSG that allows remote traffic only from public IP addresses on a safe list. The NSG should permit remote desktop (RDP) traffic. - NSGs. Use network security groups (NSGs) to restrict network traffic within the VNet. For example,...

The figure below is a graphical representation of SQL Server availability group solution   in Azure  for HADR   consisting of the following elements: A virtual network containing multiple subnets, including a front-end and a back-end subnet Two domain controller with an Active Directory (AD) domain Two SQL Server VMs deployed to the back-end subnet and joined to the AD domain A 3-node WSFC cluster with the Node Majority quorum model An availability group with two synchronous-commit replicas of an availability database You can reduce the number of virtual machines by using a domain controller as the quorum file share witness. This would reduce the number of VMs for a two-replica availability group Related: -  Creating SQL Server 2014 Always On Availability Group in an existing Azure VNET and Active Directory instance -  SQL Server AlwaysOn Availability Groups Listener configuration with Azure External Load Balancer