Pluralsight: Web Farms for Developers

- What is a Web Farm

- Web Farm is a Two or More web servers providing same service. It consists of a Load Balancer(Software or Hardware) and two or more Web Servers. A load balancer routes traffic to web servers.

- Benefits of Web Farm: Reliability and Scalability.

- Types of Load Balancers

        * Hardware Load balancer

        * Application Request Routing (ARR): Extension of IIS

        * Windows Network Load Balancing Service (NLB): Comes with Windows Server

- Types of Load Balancers

- NLB: Network Load Balance Manager could be used on Windows Server to setup and configure Web Farms.

- NLB Disadvantage: NLB doesn't operate at HTTP level, it operates at IP level. Thus, HTTP based Server health checks are not possible with this.

- ARR
        * Health Test: On certain schedule go and check that specified web page returns expected result.
        * Client Affinity: Enables Sticky Sessions.

- ARR Drawback: can be used only for HTTP traffic. Can't be used for Mail or other Non-HTTP traffic.

- Some web farms support Sticky sessions using Cookies.

- Web Farm Management

- Every single web server has to be identical.Virtualization is easiest way of ensuring this.

- Staging Server is necessary to deploy code on Web Farm. This is where code and configuration are verified.

- MSDeploy\WebDeploy is utility from Microsoft to perform automated deployments.