In our invitation, we specified that products should scale to support several hundred clients across multiple servers. Although all the entries meet this requirement, some are better suited to larger deployments. For example, offerings from Citrix, Jetro and Tarantella provide server-agnostic clustering and the ability to set metrics and conditions for balancing load. In addition, four out of five products tested contain built-in support for enterprise directories, such as Microsoft's Active Directory. NeTraverse is the odd one out here. The Citrix and Tarantella remote-display servers provide the most complete reporting and monitoring capabilities.
When we were gearing up for our tests, we thought the biggest challenge would be installing and publishing applications on the remote-display servers. We thought wrong. To our amazement, application publishing was a breeze, though each product has its own options for publishing apps, some more feature-rich than others. While we're on the subject, note that not all apps are suited to SBC. For example, graphics-intensive and multimedia applications will run into problems. Color depth is an issue because remote-display clients generally support only 16-bit or 24-bit color. And when the screen must rewrite often, as with games, you'll see performance problems.
Indeed, performance testing posed an interesting challenge. Our dual-CPU Pentium III 1-GHz Xeon servers, each with 1 GB of RAM, met the minimum requirements for all the products we tested, so our biggest concern was the resource demands of the test applications we planned to publish. When we finally put the ax to the grinder, all the products easily handled a 10-client load without change in responsiveness, but with 20 clients things slowed down noticeably. Jetro CockpIT impressed us by handling 30 clients running our text mix with tolerable performance. In contrast, rival products either rolled over under a 30-client load or showed response times in the "poor" category, defined as "too slow to be useful."
Our Editor's Choice award goes to Citrix's feature-packed MetaFrame Presentation Server 3.0, Enterprise Edition. Although it is the most expensive and complex product we tested, it turned in consistently strong results across our grading criteria.
Everything about MetaFrame told us its sights are set on the enterprise. The built-in installation manager helped us deploy packaged applications to each presentation server in the farm, making installs and updates to multiple presentation servers a snap. Once we published an app, we could load-manage it across presentation servers using several different metrics, including application or server-user load, CPU, client IP address and memory or disk utilization. To help administrators determine which metrics will best balance the load, the product can monitor real-time activities by user, application or server. No systems admin can afford to stare at a screen all day and wait for something to happen, but fortunately, SMS, SNMP and SMTP alerts can be sent based on any resource being monitored. To test this feature, we set an SMTP alert to warn us when more than 10 users accessed our published word-processing application.
