5 Load Balancers You Need to Know
July 31, 2011
Load balancing refers to spreading a service load among multiple server computers. Balancing ensures maximum service availability by offering network traffic distribution services. For example, if your business has a primary business domain (e.g., www.yourbusiness.com), you want your site available to your current customers and your potential customers 100-percent of the time. Using load balancers will provide this level of availability.
When technical folks discuss load balancing, they generally mean hardware devices dedicated to the task of balancing network traffic loads. A load balancer is a server computer with a very specialized operating system tuned to manage network traffic using user-created rules. Enterprises and hosting companies rely on load-balancing devices to distribute traffic to create highly available services. This list highlights five of those products.
In addition to providing simple distributed service to multiple servers, load balancers help prevent denial-of-service attacks, allow legitimate users uninterrupted service access, protect against single point of failure outages and prevent traffic bottlenecks to systems.
1. F5 BIG-IP Load Traffic Manager (LTM)The BIG-IP product family has a solution for almost any budget and application. If you're an F5 shop, the good news is you'll enjoy the same easy web-based administration interface included with other F5 equipment. Your load balancers can also handle your SSL certificates, which removes the pressure from your web servers and places it on network gear where it belongs.
One of F5's major features is its WAN Optimization Manager, which speeds data transfers over the WAN and enables traffic between data centers to be optimized, encrypted and highly available. This feature makes creating a WAN-based disaster recovery (DR) solution easy and almost automatic.
Every Cisco IOS-based router product has load balancing capabilities. This is exciting for Cisco shops because they don't have to buy separate hardware; simply add load balancing rules to your current equipment. Cisco is the clear leader in the router space, and included features like load-balancing capabilities is one of the reasons why.
Cisco's IOS includes every possible server load balancing feature possible, including port-bound servers, sticky sessions, TCP session reassignment, automatic unfail, slow start, SynGuard, dynamic feedback protocol, NAT, maximum connections and complete server load balancing algorithms to name a few.
Cisco's service and support are also second to none. Similar to another large company's time-tested adage, you'll never get fired for buying Cisco.
3. Radware AppDirector OnDemand Switch Series
Radware offers an array of network appliances to suit any load balancing requirement. Units are affordable, scalable, and smart. Smart goes a long way in contemporary data centers and Radware employs such smart technologies as health monitoring and detection, stateful persistency, high availability, redundancy, traffic redirection, global load balancing, denial of service mitigation, and significant performance optimizations.
Some notable features of Radware devices are easy updates and upgrades, application-aware services, and improved application response time through smart caching.
4. CoyotePoint Equalizer Appliances
CoyotePoint offers enterprise-level load balancing solutions at affordable prices. If your business sites and applications aren't enterprise-sized but require enterprise capability, you're in luck with CoyotePoint's array of products.
CoyotePoint's appliances support all web-based applications, including PHP, ASP, Oracle and Apache; Microsoft products, including SharePoint, Exchange, Outlook Web Access and Remote Desktop; and SSL VPN, Database clustering, Email services and Streaming Media.
The appliances fully support industry standard round-robin and weighted load-balancing algorithms.
5. Barracuda Load Balancer
The Barracuda Load Balancer includes standard load balancer features, plus intrusion prevention. That's right, intrusion prevention, not just detection. Prevention means your network has protection, even if you miss a critical patch or update. Barracuda's update service keeps your system ready to protect you from new threats automatically.
The Barracuda Load Balancer also includes service autodiscovery to ease the pain of initial configuration. Manage your changes, updates and configuration maintenance through the easy-to-use web interface. Other notable features are global load balancing and content caching.
Ken Hess is a freelance writer who writes on a variety of open source topics including Linux, databases, and virtualization. He is also the coauthor of Practical Virtualization Solutions, which was published in October 2009. You may reach him through his web site at http://www.kenhess.com.