When news provider CNN decided to go online, their powerful networking technology allowed viewers to customise how content is delivered
Over a period of several months, CNN and Novell had a number of discussions on how CNN's web business might be able to utilise various technologies offered by Novell. "The Novell team originally came down to do a presentation on Digitalme," explains Monty Mullig, Vice President of CNN Interactive Technologies. "We immediately noticed the directory service that powers Digitalme. It clicked in our minds that NDS might be able to address a problem technologically that we were working on in a different space."
CNN wanted to deliver personalised content on their home pages - CNN.COM, CNNFN.COM, and CNNSI.COM. With these pages acting as the main portals to their sites, they couldn't afford to allow personalisation to affect performance negatively. "They wanted their front pages to have at least four or five blocks of customisation," states Duane Bourgeois, Novell System engineering manager with responsibility for the CNN relationship. "So when you hit CNN.COM, you might see your top five stocks or weather for a couple different zip codes. They were looking at various Internet solutions as well as developing it in-house on their internal database, but after doing some research they recognised the performance characteristics weren't what they needed."
Suitability to task
"It became apparent to CNN that this application needed much greater performance than their internal database was designed to deliver, so other solutions were sought," explains Mullig. "They started looking at other solutions. They needed to find a system that could quickly retrieve user preferences and then personalise the content. As a result, the needed solution would be required to handle a lot more reads than writes; a situation ideally suited to NDS' strengths. We started down the track actually looking at products developed in the Internet space as opposed to the traditional directory. But they didn't have the performance or the flexibility of an accomplished directory structure such as NDS." Still, before CNN was willing to consider seriously the NDS eDirectory they wanted empirical proof that it was up to the task.
Meeting the requirements
CNN had very specific performance and scalability requirements that NDS needed to meet. CNN needed to be able to service 2,000 requests per second with 100 per cent success. Some of that time would need to be allocated to DNS resolution, wire latency, and injection of personalised advertising, leaving only 250 milliseconds for NDS to do a directory lookup and personalise the content.
With CNN's requirements in hand, Novell headed to its SuperLab for proof of concept. "In the SuperLab we implemented a basic off-the-shelf configuration," says Bourgeois. "No special cards or disk controller caching on the box, just standard NetWare 5, RAID drives, 100Mbps Ethernet, and 1GB of RAM."
The Novell team tested 50 NT workstations, each doing ten requests per second against a single NetWare server running NDS. Without taking advantage of NDS replication and multiple servers running NDS, the single directory server handled 500 requests per second with less than 60 milliseconds of latency.
Regarding the testing, Andrew McBride, Novell Enterprise Account manager relates: "After we determined the response time was there, it then became a matter of scalability. The SuperLab set up a situation using billions of users and the latency was still there." The test results clearly showed that the linear nature of NDS response times could easily meet CNN's performance requirements.
"We were looking for NDS to do very fast retrieval with very high data volumes on individual Web queries," says Mullig. " It performed well within our performance requirements."
With positive test results in hand, CNN Interactive decided to first conduct an in-house pilot test using NDS eDirectory. This in-house testing ultimately led them to make the decision to go live with NDS as their user profile solution.
Ultimately, CNN decided to implement NDS on a NetWare 5 platform using four Compaq ProLiant 6400s, each with 2GB of RAM. Each directory server dedicated 1.5GB of memory to NDS and the remaining 500MB was allocated for NetWare 5. Each server also had three 100Mbps Ethernet cards, although the current load only requires one to be activated for now. Two of the cards will eventually be load balanced (one IP address) and bound to LDAP to address future scalability. The other Ethernet card will be able to be put on a separate subnet to handle communication between the NDS servers.
From the beginning, CNN decided that they would not sacrifice performance for personalised content. They would rather deliver generic content quickly than make a customer wait for personalised content. "They didn't want to leave their customers hanging," explains Novell's McBride. "NDS provides both the speed and the scalability." NDS outperforms competing directories, especially as the number of users increase. Other directories' LDAP search capabilities decrease in direct proportion to the number of users added to the directory. NDS eDirectory's linear search characteristics enable it to deliver high performance even as millions of users are added to the directory.
With a year 2000 goal to double their online audience, CNN has confidence that the performance and the massive scalability of NDS eDirectory will easily stay ahead of their growth and handle the expansion of their e-business. "NDS has both the features and the performance characteristics that we need," states Mullig. "We're very pleased with the product."
Compiled by Will Garside from http://www.novell.com
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