On the Mark: 4/15/2003

	Tuesday, April 15, 2003

Using UDDI When does it make sense to dynamically discover and use a web service as opposed to doing so at design time? I suppose its worthwhile if web services are frequently moving around, but how much does, or should, that happen?

The dynamic usage sounds like a lot of overhead to me. Programmatcially querying a UDDI server probably isn't that bad, but retreiving the WSDL, generating a proxy, and then compiling the proxy sound like time-consuming activities. Something you just wouldn't want to do very frequently. That suggests you may also want a caching strategy. At this point we have traded development complexity for placement flexibility. Is it worth it? Has anybody pursued dynamic web service discovery and usage? What were your experiences?

11:07:38 AM

Web Apps and Web Gardens in IIS 6.0 One area of our company is already pursuing server consolidation. Their approach has been to take four ASP.NET applications and house them together on a single W2K machine. All were built on a common framework and all belong to the same business group. However, the design showed a flaw when one application "misbehaved" (waiting on a long-running DB2 transaction) resulting in no ASP.NET activity for three minutes after which the ASP.NET worker process was recycled - effectively taking down all four applications. Windows 2000 and IIS 5.0 just don't provide the kind of application isolation necessary for this approach to work.

Windows Server 2003, on the other hand, sports a completely rearchitected IIS 6.0. A key feature of the new architecture is that a web application can be placed in an application pool. Each application pool receives its own worker process. Similarly, multiple processes can be dedicated to a Web Garden - a single machine version of a web farm. Misbehaving applications are a fact of life. We need to address those problems as they are uncovered, but we must also avoid putting one app at risk because of another that misbehaves. IIS 6.0 seems to provide a solid solution.

11:01:44 AM

Virtual Machines. A major topic of discussion during last week's briefings on Server Consolidation strategies was virtualization software - VMWare and Connectix (now part of Microsoft's Windows Server 2003). These both look like promising technologies for hosting, and isolating, multiple test/development environments on a single server. This will be a major component of our server consolidation strategy.
10:47:16 AM