Caching in on Data
New caching technology is poised to dramatically increase the speed, accuracy and scope of dynamic information that is distributed over the Internet.
Innovative caching methods such as CDNs (content delivery networks) aim to speed delivery of crucial data by using policies to govern data delivery. In the case of CDNs, the policies ensure that frequently requested data is moved as close as possible to the user, usually by relying on a network of geographically dispersed servers.
Emerging technologies are likely to dramatically increase the accuracy of dynamically generated content by ensuring that only the right information is cached. This capability could make it possible for businesses of every stripefrom banks and brokers to e-tailers and search enginesto significantly boost the variety of Web-based offerings without incurring substantial new costs.
The reason is pretty simple. As repetitive processing is offloaded from application and database servers, this frees up processing cycles to handle other tasks.
However, CDNs also introduce new administrative problems, most notably the headache of keeping distributed caching policies up-to-date. In addition, CDNs rely on software and often specialized hardware that must be added to the network to get productivity gains.
Despite these concerns, eWeek Labs believes most organizationsincluding those that have battened down the hatches to weather the current economic stormshould evaluate CDN technology because it will improve most Web application performance while significantly decreasing the need for new back-end servers.
A variety of caching vendors, including Ipedo Inc., maker of caching tools for databases; CacheFlow Inc., which makes Web cache appliances; and SpiderCache Inc., a dynamic content accelerator (see review, Page 63), are taking Web caching to a new and more useful level by making dynamic content more accessible. Web caching has traditionally focused on speeding the delivery of static HTML Web pages (see story on HTML caching, right).
IT departments using content delivery services from companies such as Akamai Technologies Inc., Digital Island Inc. and Inktomi Corp. should keep a watchful eye on how these companies support dynamic content caching. For example, Akamais FreeFlow service is partnered with CacheFlows appliance, allowing Web page content to be customized based on each sites policies. IT managers should keep abreast of these developments because the deals often require special hardware and software in the enterprise.
Here come the heavies
Internet Service Providers arent the only players who are getting into the CDN game. Networking giant Cisco Systems Inc. has announced products and services to facilitate CDNs, and database heavyweight Oracle Corp. is focusing on dynamic caching as well (see Tech Analysis of Oracle9i starting on Page 61).
Which brings us to the ticklish question of dynamic content caching. Its ticklish because, at its heart, dynamic caching is an oxymoron. Vendors of dynamic caching products are offering IT managers a way to clear the cache and refresh it with the correct information according to a variety of conditions.
Putting these conditions together with the mesh of Web, application and database servers, along with the network infrastructure to support the whole thing, is a truly daunting problem, but its a problem that is definitely worth solving.
Unlike quality-of-service implementations or additional high-speed network connection installationmethods that rely alternately on throttling and increasing network capacityCDNs attempt to harness the current network infrastructure more efficiently. As network usage increases, and especially if streaming-media technology takes off, it is likely that both methods will become necessary for networks to carry the load and remain cost-effective.