Products: Local Load Balancing
Copyright © 2004 Open Enterprise Systems, Co., Ltd.
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April 18, 2004
This document will discuss a technique, which Open Enterprise Systems (OES) employs, to utilize a redundant web server cluster on an LAN to deliver one seamless service. This technique fulfills the following usage requirements:
- High Throughput. The cluster is able to service requests at a higher rate than one server alone. The throughput of the cluster should scale linerally with the number of servers in the group.
- High Availability. If a server experiences a problem (for example, a software or hardware crash), the machine will be removed from the availability pool, and all further requests for service will be routed to the other servers.
- Flexibility. This system must work with all major TCP/IP services, including web services (including HTTP and HTTPS), email (including SMTP, POP3, and IMAP), and databasing (including LDAP, ODBC, and any databases that support replication, such as Oracle, PostgreSQL, and MySQL).
- Transparancy. Some services, such as web shopping with cookies, require one server to handle a user transaction persistantly. For example, shopping carts using cookies and SSL have this requirement. The service must be able to persistantly deliver a user request to the same server if necessary.
The most effective method to meet these criteria is using a smart router to dynamically route new incoming requests to the available servers in the pool.