Version 7 load balancer a fine fit for Web sites without gigabit needs
Switch-based load balancers are a necessity for almost any high-volume Web site. But smaller Web sites with T-3 or 100Mbps Internet connections don’t need gigabit functionality and may be better served by router-based load balancers such as the Coyote Point Equalizer E-350. Coyote Point is one of the oldest players in this market, and it shows in the maturity of its software, interface, and functionality.
Like its siblings, the E-250 and the E-450, the E-350 is based on a 1U server chassis running BSD’s and Coyote Point’s specialized software. It has two Ethernet interfaces, one forthe external network and one for the internal network. And this most recent version adds layer-seven functionality, including cookie-based persistence, SSL session ID or URL, and distribution to specified servers based on the type of content.
With all its features, the E-350 is a great value. Although it won’t handle the kind of throughput that switch-based products will, most Web sites don’t need that kind of throughput.
I tested a prerelease version for this review; the final product ships on May 5. The feature set was complete, but the product wasn't yet optimized for performance. The final version should handle higher traffic loads with multiple rules.
Initial setup must be completed through a serial terminal. The process is easy -- as long as your serial terminal is completely VT100 compatible -- and navigating the setup dialogs is straightforward. Logging in as "eqadmin" automatically takes you to the IP configuration utility, which takes you through setting the IP addresses for both interfaces. The utility then aids with netmask, host name, and passwords for the eqadminand Web administration accounts.
After reboot, administrators can complete the configuration process using a Web interface. For security purposes, access to the root account on the devices is limited to the serial console. This should be adequate security for any application where physical security is enforced. A hacker cannot telnet into the box and hack the root account, and the basic TCP/IP parameters cannot be changed through the Web interface.
Coyote Point will soon offer an SSL hardware acceleration module. This will be sold as an add-in card for the E-350 and E-450 models and should support hundreds of SSL transactions per second.
Creating a virtual cluster is simple with the Web interface. The menus are clean and uncluttered with full access to all the features. With the E-350, clusters can contain up to 16 servers; the number of clusters is unlimited. Administrators create clusters based on the IP port, which means you can create separate clusters for Web servers, SMTP servers, and FTP servers, all using the same groups of physical servers if you so desire.
The solution supports all the common load-balancing algorithms using agents, including fastest response, fewest connections, adaptive, static weights, round robin, and actual server load.
The optional Envoy software also adds the ability to balance loads based on observed network latency. Geographic load balancing is available as an option, allowing clients to be directed to the Web site geographically closest to them in a geographically distributed virtual cluster.
Health checking is available both by pinging to see if the TCP/IP port responds and by retrieving a URL from the Web server and ensuring that the proper content is returned. The solution supports spoofing, so servers can return client traffic directly to the client instead of directing that traffic through the E-350.
Each protocol has its own set of parameters that can be used to make load-balancing decisions.For example, with HTTP the Equalizer can direct traffic based on the client HTTP version, the host name, pathname, filename (including filetypeprefix or suffix), URL, the filename requested, or text-matching against the HTTP request header. The solution supports booleanexpressions for match rules as well.
Some expressions will put more of a load on the Equalizer than others. When I set up the product to direct traffic based on file extension (.JPG and .GIF files from Server1, all the rest from Server2 and Server3), the E-350 was able to route about 35Mbps of traffic to the servers with an average response time of less than half a second for all traffic. This is about what I expected, based on the T-3 capacity of the E-350.
But when I changed to routing traffic based on matching one of several specific text strings within the HTTP request, total traffic dropped to about 14Mbps, and average response time went up to about one and a half seconds. Administrators would do well to limit the number of text search expressions or use the higher-speed E-450 model.
The wizard for creating match rules was not available in the version we tested, but editing the text file that stores the rules is simple.
To verify the load-balancing functions, including failover, I killed the server process on a server in a cluster then deleted pages that the Equalizer was checking. In both cases, the Equalizer was able to quickly discover failed servers or missing pages and routed traffic to the other servers in the cluster.
The Equalizer E-350 is a capable router-based load balancer with an exceptionally low price, easy setup, and a host of sophisticated features. It should perform adequately for any Web site with a T-3 connection or slower. If you have a connection faster than T-3, consider the higher-end E-450.
Overall Score (100%)
|Coyote Point Equalizer E-350 Version 7.0||8.0||9.0||9.0||9.0||8.0|
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