Introduction
Resonate is pleased to respond to Acme Websystems' Request for Proposals for a Load-Balancing solution. We are confident that we have a solution that will meet your current needs as well as accommodate increasing complexity in your E-commerce architecture. Our products have proven themselves in both corporate information and e-commerce deployments with customers including BankBoston, Discover Brokerage, and E-Trade.Summary
Resonate's family of products is based around our Central Dispatch product, which we recommend you use to provide load-balancing services for your eight Solaris web servers. The Central Dispatch product enables you to ensure that individual requests are sent to the most available, fastest-responding servers. As a software solution, we are able to constantly monitor server health and use detailed information via agents installed on the servers. This answers your requirement that CPU utilization be taken into account (in addition to number of connections, server response time, and service type). With Central Dispatch, the ability to take all of these factors into account is built-in to the product. In addition to load-balancing based on all of the above criteria, Resonate believes that evolving sites need to take additional factors into account in the load-balancing decision, such as application, file, and database server health. Our newest product, Commander, is aimed at answering the challenges of these sophisticated web architectures by monitoring these resources and establishing automated actions which occur when problems are encountered on these resources (e.g. the ability to disable a web server if it loses access to a vital application server). By selecting Central Dispatch for providing load-balancing services, you will be able to begin use of Commander with your already previously Central Dispatch software.Basic Operation
The Central Dispatch product consists of software that you load onto each of your eight web server systems. Once that software is installed, you no longer need to touch those systems in order to configure load-balancing settings. Using our Dispatch Manager Java application, running on any of your system administrator's desktop systems, you connect to the site and can configure Virtual IPs (VIPs), real servers and the load-balancing algorithm used to decide which server should be used. You will find that the Central Dispatch solution answers all of your requirements of choosing an eligible server based on the number of connections, response time, CPU utilization, as well as the ability to send traffic of different types (HTTP, FTP, and SSL) to different servers. The method of operation which Central Dispatch uses to perform load-balancing is that one system in your cluster is configured in the user interface as the scheduler system. Inbound traffic is sent to the scheduler, where it is examined and a server is selected to satisfy the request. At that time, the scheduler uses a process that we call the TCP Connection Hop to transfer the connection to the server that will satisfy that request. Once the server receives the connection after the Connection Hop, it is able to respond directly to clients, allowing high-volume outgoing traffic to be sent back to the client without burdening the scheduler system with additional work, which would slow it down. You will be pleased to know that included with any purchase of Central Dispatch is the ability to have a back-up scheduler system that automatically becomes active in the event of a Primary scheduler failure. In addition, servers in a Central Dispatch site are accessible via one or more virtual IP (VIP) addresses, appearing to clients as a single internet site allowing multiple servers to act as back up to each other. This is another example of the way that Central Dispatch provides you with the flexibility to accommodate your future needs as traffic and complexity grows in your site. Resonate offers a number of other features which are likely to be used as your E-commerce business continues to grow, such as the ability to base persistent session tracking on an SSL Session-ID. Resonate has a history of implementing features targeted at the rapidly evolving needs of e-commerce customers.Performance Problems
We feel that a scalable architecture (such as we've proposed) with the ability to add additional nodes is the best answer to solving your current performance problems. Because of Resonate's unique capability to factor CPU utilization information into the load-balancing decision, we are confident that we will make most efficient use of your existing web server resources. If you are concerned about your SSL services in particular (with overhead from encryption/decryption eating up your CPU resources), we can suggest add-in boards for your web servers which will allow each web server to service significantly larger numbers of SSL clients at one time. These solutions are consistent with the ability to scale your site through the use of additional server nodes.Migration
Central Dispatch is able to offer an extremely easy migration path from your existing Round-Robin DNS system. You can continue to maintain your Round-Robin configuration during the installation of Central Dispatch and simply change your DNS entry to a single Virtual IP managed by Central Dispatch. At that point, clients will gradually begin to use the newly load-balanced cluster, as the DNS change propagates out to DNS servers on the Internet. Because of the ease of migration, we do not recommend the use of Network Address Translation as part of the initial load-balancing solution deployment. If you choose to deploy NAT at the same time as your deployment of the load-balancing solution, your web servers will be inaccessible at their old IPs (for which clients on the Internet have the IPs ), which will ruin a transparent deployment. If you need to deploy NAT in the future, we recommend that you use Resonate with a router or firewall to provide NAT services. We recommend that you carefully consider the method for deployment of alternative solutions to determine if a transparent and zero-interruption deployment is possible.Content Replication and Verification
In your RFP, you repeatedly mention problems with maintaining identical copies of HTML code on the multiple servers. It is our experience that content replication technologies are difficult to deploy and administer. The majority of our customers instead choose to utilize a network storage device which allows them to have access to the HTML repository over the network, relieving them of the need to try to replicate that content onto multiple servers. We believe that this recommendation will allow you to focus your web server monitoring attention onto other potential problems, rather than devoting a large amount of server resources to maintaining a consistent copy of the HTML document repository used at your site. In order to provide a more robust e-commerce service, we recommend that you consider migrating to use our Commander product in order to take into account the health of other mission critical resources that your web presence depends upon. This will allow you to not only have insight into the health of your front-end web servers, but also the back-end resources which you deploy as your site continues to grow in complexity. In addition, to Commander, we also offer a complementary product called Global Dispatch which will allow you to expand your infrastructure to multiple geographically distributed Points of Presence (POPs) as you need additional scalability and faster response times.Support
Resonate offers a range of support options, including 24x7 telephone support. We also have a professional services offering which can be utilized for education, training, product installation and customization services.Pricing
Our recommendation for your solution carries a cost of $44,000, which includes server licenses for eight nodes as well as the ability to schedule for an unlimited number of Virtual Ips and services.Conclusion
Resonate is confident that we offer the best solution to address your current and future needs for load-balancing your corporate information and E-commerce servers. RELATED LINKSBack to the RFP and other responses
Load balancing forum
Discuss load balancing with Mark Hoover, author of our article on load balancing trends.
Balancing act
Review: load balancers Interactive buyer's guide
User study: Dense traffic drives Web-server load balancing
Don't be swayed by fancy features when a fast, scalable load balancer should be your top priority.
All nine products we tested improved Web server performance significantly, making it tough to select a single winner. But in the end, the fastest product under the greatest load, Resonate's Central Dispatch, won our Blue Ribbon Award. Network World, 6/14/99.
Find a product that best matches your criteria, compare two or more load balancers in several categories or download a spreadsheet with all the product data.
With nearly 60 Web servers, the West Group needed load balancing quickly. See what they decided on and why. Network World Fusion, 6/14/99.
