By Alex Soo, PEER 1

As online companies and businesses grow there comes a point where it becomes necessary to rethink the design of the server solution. There are several ways to accomplish this, from splitting the different applications onto separate servers, to upgrading hardware and adding additional machines. Whatever the design is, the goal is to focus on improvement in 3 areas:

• Increased capacity
• Scalability
• High availability/redundancy

PEER 1 Dedicated Hosting allows companies to achieve all of these goals by offering a robust hardware Load Balancing product.

Description of technology offered by PEER 1
PEER 1 offers a shared Load Balancing platform that utilizes a pair of Foundry Server Irons in Active/Active mode for redundancy. These devices are configured to allow different groups of servers (server farms) to appear as a single "virtual" server that shares a single "virtual" IP address. Requests come in on this virtual IP, which you can assign to any domain name, just like a real IP. The Load Balancer then takes care of the rest, distributing the traffic among the servers. Unlike clustering, Load Balancing does not include any cooperation or content sharing between the load balanced servers. As a result, high-traffic applications with static content such as web or FTP servers are ideal candidates for this type of solution.

Features and benefits
As previously stated, the PEER 1 Load Balancing product enables customers to design a highly effective and highly scalable solution which focuses on the following areas:

Increased Capacity - Using a "least-sessions" algorithm, requests are distributed amongst multiple servers hosting the same application, allowing more users to reach your application.

High Availability/Redundancy - Since servers are automatically removed from the farm when health checks fail, Load Balancing is an excellent product for customers seeking High Availability for HTTP, SSL, and FTP applications.

Scalability - Servers can be easily inserted or removed from the server farm, allowing customers to react quickly and resize their web presence to match demand without costly server upgrades.

How it works
Load Balancing is a fairly simple process:

• A Virtual IP (VIP) is assigned to the application to be load balanced.
• Requests to this VIP address are processed at the Foundry Server Irons, where it checks for the availability of the "real" IPs on the servers.
• Requests are then distributed amongst the available servers. Servers that do not respond to a health-check do not receive any traffic.

Fig 1. The flow of data in a load balanced solution

Server configuration
Servers should be identical in regards to the hardware and application. Since the Load Balancer does not provide replication it is imperative that changes made to the code/application on one server be reflected on the other server(s) in the rotation. Applications are bound to both a real IP address and the Virtual IP address as well. Purchase of the Load Balancing product includes the setup of these IPs to simplify the process.

Load balancer configuration
PEER 1 utilizes a pair of Foundry Server Iron XLs in Active/Active mode for maximum availability in the event one of the appliances should fail. These devices are setup to distribute traffic to the server with the least sessions. Some functions, like e-commerce, require sessions to remain on the same server. On request, the Load Balancers can be configured for "sticky sessions". This will send successive requests from the same client to the same server they were on, thereby preserving session state for the application.

PEER 1 support included
PEER 1 will fully manage the Load Balancers on a customer's behalf, thereby simplifying the overall administration of the solution. PEER 1's technical staff will be more than happy to assist with any questions or configuration issues with the product. We also have engineers available to review your current solution to see if it is a candidate for Load Balancing. For further information please contact your Account Manager to schedule an appointment.