Load balancers from F5 Networks and Zeus Technology tip the scales
F5 BIG-IP and Zeus ZXTM traffic managers offer choice between polish and price
My testing involved setting up several servers with the same Web site, a demo version of an e-commerce application. Each load balancer was used to create a virtual cluster of the servers, which varied in processor number and power. I then used an Ixia 400T traffic generator and IxLoad software to simulate a large number of users accessing the site. Both load balancers were able to keep actual loads on the servers consistent even though the servers’ processing capabilities varied considerably. I then enabled a number of features such as SSL sessions and application security, and attempted to overload the load balancers by simulating many simultaneous users. In both cases, overloading these systems was possible only with artificially small sessions. When simulating traffic, the gigabit connection became saturated before the limitations of the BIG-IP 6800 or ZXTM 7000 were reached.
Both products offer a wide array of features, including service-level management and bandwidth shaping, DoS (denial of service) protection, session persistence based on URL, cookies, header information, and other methods, and support for Web services as well as XML, XPath, and XSLT. Their application acceleration capabilities include compression for many Web applications, not just HTML, and both units can balance loads across multiple sites as well as multiple servers at a single site. F5 and Zeus both supply scripting languages and APIs for integration with corporate applications.
Some of these features are options that cost extra. Zeus has an advantage here, as more features are included in the base price (see table), although F5’s versions of the features are usually more sophisticated and easier to deploy. For instance, the ZXTM 7000 includes HTTP filtering to protect against exploits, but you must download a definitions file from the Zeus Web site and add definitions manually. F5’s ASM (Application Security Module) protects against more kinds of attacks and has an automatic update service. On the other hand, the ASM costs an additional $12,500.
F5 BIG-IP 6800
F5 Networks has been making load balancers for a decade, as long as any company in the business. The company’s product has evolved over those years into a sophisticated, feature-rich, and easy-to-use appliance. Given the wide array of complex tasks that the BIG-IP can perform, the product is no more complicated than necessary. The management interface is clean and easy to navigate, and shortcuts take the tedium out of tasks that require repetitive data entry, such as adding servers to a virtual cluster.
Packed with plenty of switch ports, the BIG-IP is not only suitable for Internet applications, but for internal Web-based applications that may require multiple gigabit links for optimum performance. My test device was limited to eight gigabit Ethernet ports, so I wasn’t able to determine whether the BIG-IP is non-blocking across all ports, but it certainly can handle eight gigabits of Web traffic without introducing much overhead or latency.
The BIG-IP’s huge feature set doesn’t come cheap. It would be easy to spend upwards of $150,000 for a two-unit fail-over configuration with all the features enabled, plus a substantial yearly subscription to updates and support. On the other hand, a pair of BIG-IP’s should be able to support even the largest commercial sites without a hiccup.