Citrix upgrade reduces Web server requirements for Web 2.0 apps

Citrix has upgraded its NetScaler Web application-delivery appliance to support two-way proxying that cuts the numbers of servers needed for highly interactive Web 2.0 servers.

Called NetScaler Web 2.0 Push, the software manages connections between users and Web servers in both directions. Previously the software managed and streamlined user-to-server connections to reduce the load on the server, but didn't do so for traffic headed in the opposite direction.

With real-time interactive Web applications growing, the software addresses the increasing load on servers to maintain a high volume of outgoing connections, says Julie Craig, application management research director for Enterprise Management Associates.

Citrix competes in this area against Cisco, F5 Networks, IBM and Juniper, Craig says. "I have not heard of anyone else doing this," she says.

Rich Internet applications that connect to thousands of users simultaneously are increasing and creating huge server loads, she says. For example, an online auction site may have many bidders on a given item and each needs to be told of the latest bids as they happen, which boosts the number of users the Web server must maintain links with.

Web 2.0 Push offloads some of that burden by maintaining links to the individual users and dispersing bid information to them as it comes in via a single connection with the server.

Citrix says the reduction in the need for servers can be dramatic. A European firm with Web servers that get 500,000 hits a month has 1,024 servers and plans to reduce that to 200 by using Web 2.0 Push technology on its NetScalers, Citrix says. Another NetScaler customer believes it can reduce the number of Apache Web servers in its network from 220 to between 14 and 16 servers, Citrix says.

"I have to take their word for it that these reductions occurred," Craig says, and the types of Web applications running on the servers could influence the results. "But whether it’s 90% reduction or 50% reduction, in this business a 10% reduction of servers is huge. This will be as important as load balancing was for traditional server applications."