Application serving
What's the best choice for running application servers such as WebLogic and WebSphere? What about thin client software such as Citrix MetaFrame or Microsoft Terminal Services?
Kevin McIsaac: META predicts that Windows 2000 will become the dominant operating system for mid-tier application servers during 2002, due to growing ISV reference platform momentum.
Linux on Intel--"Lintel"--will be successful as a Web and appliance server OS, but application server penetration will be minimal.
The decision over which operating system is "the best" technically (e.g. the most robust, or offering the highest performance) is no longer a primary consideration. Instead, users should adopt the following principles, which lead to greater infrastructure flexibility and reduce total cost of ownership:
-
1. Simplifying the complexity of the datacentre environment by reducing the number of different operating systems;
2. Increasing infrastructure agility through use of common platforms and common configurations;
3. Exploiting the commodity curve by adopting commodity hardware and operating systems.
Other than Solaris, Unix has already lost the mind share battle for software vendor development. Our research indicates users are finding it increasingly difficult to run new applications exclusively on HP-UX, AIX, and Tru64 Unix.
Peter Menadue: Unix has always been a fundamentally good operating system, but has never lived up to the early promises of environment uniformity. The ranks of the Unix variants have slowly been thinning, and I think some rationalisation will continue.
Kevin McIsaac: Most new applications are being implemented using a multi-tier architecture with a back-end database management system server, multiple middle-tier application and integration servers, and numerous Web servers.
Although Oracle is supported on all major operating systems, most application and key middleware software is not. Aside from Solaris, NT and increasingly Windows 2000 already dominates as the middle-tier application server reference platform of choice.
The application server provides a robust, scalable, managed environment for executing a process. For a business application, it subsumes the functionality traditionally provided by the midrange operating system, such as process scheduling, memory management, load balancing, high availability, and security.
The application server and database manager provide a thick layer over the top of the OS that augments, extends, and subsumes the services traditionally provided to an application by the OS.
From an application perspective, the OS becomes a hidden service layer that supports the application server and database manager by abstracting the hardware.
While the OS remains a necessary service, its importance to an application is greatly diminished. Just as the adoption of the relational database altered the value of midrange OSes such as VMS, Prime OS, and Unix, so too does the adoption of the application server.
The elimination of Unix's traditional advantages over Windows 2000--high availability, failover clustering, and scalability--enables Windows 2000/Intel vendors to compete on functionality with Unix/RISC vendors.
The load balancing and failover features of the application server enable a highly available, highly scalable service to be built from a farm of low availability, low performance, commodity servers.
Scalability is cheaply and naturally achieved by simply adding more servers to the farm.
Unlike scaling a single image system, the application server can dynamically add or remove additional processing power without bringing down the application.
The application server is able to provide better failover and clustering services than the OS because it has a greater awareness of the application structure and requirements.
When building the application server tier, clients should implement a farm of servers with 4-way Intel or 4-way SPARC hardware running a commodity operating system--Windows 2000, Linux or Solaris. While Linux on Intel is a potential choice, there are few reasons except religious passions why Linux would be chosen over the widely accepted and better-understood Windows 2000.
By 2004/05, we believe Unix--other than perhaps Solaris--will be viewed as a legacy platform. However, by 2002/03, the choice between Microsoft's .NET and Sun's J2EE as an IT organisation's primary enterprise application integration framework will largely dictate the underlying operating system and server hardware platform options, especially for middle-tier application and integration servers.
Moreover, Intel IA-32-based servers with four to eight CPUs are already appropriate for 80 to 90 percent of all application scalability and availability requirements, that is up to roughly 75K tpm-C. In addition, Windows 2000 is no longer coupled with Intel IA-64 hardware.
However, by 2002/03, we expect Intel to finally deliver on the promise of IA-64 performance competitive with then-high-end RISC technology.
This will begin to enable all major system vendors with the notable exception of Sun to offer more linearly priced midrange and high-end servers supporting Windows 2000.
Incidentally, we do not expect Linux to move up from the Web server tier to the application server space; instead, we believe Linux will move downstream more broadly as a "black box" appliance server operating system.
Dean Thompson: Just like database servers, application servers must be reliable and they must be able to serve the applications with sufficient speed. However, no one operating system is perfectly optimised to act as an application server.
If an organisation were predominately Windows based, I would recommend a high performance machine with multiple high-speed network cards and running Windows 2000. In a predominately Unix environment I would suggest a high performance server--most likely Sun/Solaris for reliability--connected to a high-speed network.
A growing trend is the deployment of application servers where multiple clients connect to "virtual sessions" and run the application that they want to use on the server through a window on the client's screen.
The most notable example is Citrix MetaFrame. Although the approach is a good idea, it does have a number of problems with it. In particular, it requires an incredibly high-powered machine to support many virtual sessions and computationally heavy programs.
This approach seems to be a backward step. Over the last decade we have seen the development of programs that push the processing to the client and reduce the load on the server, but the introduction of application servers moves the processing back to the server.
Creating a homogenous environment with Windows clients and servers or Unix clients and servers allows security permissions and auditing information to be preserved and observed. Trying to maintain the same level of security and auditing information for systems in a heterogenous network can cause all sorts of problems.
I find the comments about Unix versions other than Solaris becoming considered "legacy" systems rather funny. I believe it was Solaris that recently announced they would no longer be developing a version for Intel...
Furthermore; the only reason there is an "OS War" is because Microsoft is more interested in making money and increasing their market share than meeting the needs of their customers. Linux is not the one with the "secret" protocols and undocumented "standards."