Many organizations today are running critical line-of-business applications, messaging applications, and e-commerce Web sites that are crucial to their day-to-day operations. In other words, these applications and services need to be up and running. Any downtime or decrease in performance can, in the end, mean a loss of business or revenue. The features and capabilities of Enterprise Edition help organizations address the issue of high-availability and scalability.

Enterprise Edition is designed for medium to large organizations. It has all the features of Standard Server with additional features targeted for businesses requiring a high level of availability and the ability to scale applications up and out as demands increase.
Scalability or “scaling up” can be achieved by adding more horse power to a server as demands increase. One of the ways in which Enterprise Edition addresses scalability is through Enhanced Symmetric Multiprocessing (SMP). To increase server performance you can “scale up” by adding up to 8 processors. Enterprise server also includes enhanced memory capabilities, allowing you to add up to 8 GB of memory.

To provide high-availability and fault tolerance for mission critical applications, services, and data Enterprise Edition supports server clusters through Cluster Service. Cluster Service provides a means of connecting multiple servers, up to 8 nodes, together that work and appear as a single system. Cluster Service provides high availability by automatically detecting when an application or service fails and automatically restarting it one another cluster member. Downtime from failed applications and services can be as little as a few seconds and go unnoticed by users.

Keep in mind that Enterprise Edition and Datacenter Edition both support clustering. This feature is not available in Standard or Web Editions.

Datacenter Edition is designed for large enterprise organizations requiring the highest level of server performance. It is by far the most powerful operating system out of the four Windows Server 2003 platforms offering the highest level of scalability, reliability, and availability.

Unlike the other version of Windows Server 2003, Datacenter Edition cannot be purchased on its own. The operating system comes pre-loaded on a system that has been certified by Microsoft, meaning the hardware has been put through the stress tests for proven reliability. This would only make sense, why would you install a platform built for the highest reliability on hardware that is unreliable. For maximum uptime, reliability must be built into the hardware and the software.

Some of the features that set Datacenter Edition apart from the other operating system versions are its support for 32-way symmetric multi-processing and up to 64 GB of RAM (while the 64-bit version is capable of supporting 64 processors and 128 GB of RAM). It includes a technology known as hyper-threading which allows a processor to execute multiple threads simultaneously thereby increasing performance.

As with most software that is installed, there is usually a set of minimum hardware requirements that must be met, often the software will not even install of the bare minimums are not met. Since the different versions of Windows Server 2003 have different capabilities, they also have different hardware requirements. Obviously since Datacenter Edition is a more powerful operating system with additional features and designed for large scale organizations, it will have a different set of hardware requirements than that of Standard Server. The following outlines the minimum and recommended hardware requirements for each of the platforms.

Standard Edition
133 MHZ processor (550 MHZ recommended)
128 MB of RAM (256 MB recommended)
1.5 GB free disk space

Web Edition
133 MHZ processor (550 MHZ recommended)
128 MB of RAM (256 MB recommended)
1.5 GB free disk space

Enterprise Edition
133 MHZ processor (733 MHZ recommended)
128 MB of RAM (256 MB recommended)
1.5 GB free disk space

Datacenter Edition
400 MHZ processor (733 MHZ recommended)
512 MB of RAM (1GB recommended)
1.5 GB free disk space

Of course, when planning for server hardware, always take into consideration applications, services, and server role as it will increase hardware requirements.