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Like Resonate Dispatch, HydraWEB uses a server-side agent that needs to be installed on every server in a cluster. We installed the HydraWEB agent as an NT service on our test servers. Because it gathers information about each server from its agents, HydraWEB has a definite edge over the nonagent competition, such as Cisco's LocalDirector and RND Networks' Web Server Director Pro. Rather than relying on dropped requests and slower ping response times, HydraWEB's agent minimizes the number of dropped requests that the load-balancer unwittingly creates as a result of a downed server. HydraWEB agents support mo st flavors of Unix and Windows NT, so platform issues will be rare.

HydraWEB's ability to use FDDI and ATM network interface cards also gives it a slight edge over the competition. Providing throughput beyond T3 speeds at 60 Mbps, HydraWEB is well suited for large Web sites, as is its unique logical clustering, which provides maximum flexibility and configuration.

Resonate Dispatch 2.0
Rocking the balancer boat as the only software product in our tests, Resonate Dispatch stands up with a rich feature set and easy-to-use management utility. Delivering services with minimal performance loss, Resonate Dispatch is extremely flexible and easier to use and configure than Cisco LocalDirector and BIG/ip2. With innovative features, such as URL-based balancing and platform-independent management utilities, this product deserves its high grades.

Java-based management tools and real-time performa nce statistics are just a few of Resonate Dispatch's features. Unlike Cisco LocalDirector and Web Server Director Pro, Resonate Dispatch does not restrict server location, letting you place servers anywhere on the Internet or intranet. You can perform hardware upgrades yourself when you need them, instead of paying for exp ensive proprietary hardware.

In our tests, Resonate Dispatch was the only solution that parsed the incoming URL. You can set up clusters to use Resource-Based Scheduling, which deploys predefined scheduling rules that redirect incoming requests to the appropriate servers. With this capability, your fastest servers provide graphically rich, compute-intensive content only (such as database operations), while less-capable servers handle less-intense content.

Resonate Dispatch routes incoming traffic via a scheduler daemon running on one of the nodes in the cluster. This node can be a dedicated scheduler or part of a content-bearing server. Redundant schedulers also can serve content and automatically detect a downed primary scheduler, taking over scheduling tasks if primary servers fail. Server-side agents relay server load and statistical information directly to the scheduler when needed, or as requested by the network administrator.

We added a node to the cluster using the Java-based management tool in a remote lab. Within seconds, we updated and modified our cluster's configuration with a few mouse clicks. For administrative rights, users are authenticated against information that is located on the scheduler. Individual administrator and user accounts for Resonate Dispatch are specified during installation.

Server status and autoserver re-enable flags make Resonate Dispatch easy to use for routine (or not-so-routine) server maintenance. When the product determines that a server is down, it automatically re-enables the server to receive requests after a specified time. To test this capability, we killed a Web server by unplugging it, and after the scheduler detected it as down, we pl ugged it back in. After a specified 30 seconds, the scheduler re-enabled the server for requests and the server started delivering content again. Although auto re-enabling servers works well when servers reboot after a crash, this capability does not physically reboot the machines and will waste time if a machine isn't rebooted .

After our virtual server and cluster were up and running, Resonate Dispatch performed surprisingly well in our tests. Not quite beating out the fourth-place finisher, Resonate Dispatch fell behind Web Server Director Pro and the other three balancers. During another test run, we monitored the individual node status using the real-time monitoring software incorporated into the management software.

To download an Adobe Acrobat .pdf format version of Web Server Redirector Features, click here.

Internet Rx
by Chris Lewis


Updated July 31, 1997