Why Is Server Core Useful?
To decide whether and how to implement Server Core in your environment, you need to understand the benefits that Server Core can provide and some possible usage scenarios for the platform.
Benefits of Server Core
Before we look at the benefits of Server Core, let's debunk a misconception: Improved performance is not one of the benefits of running Server Core instead of a Full installation of Windows Server 2008. This may seem paradoxical until you realize that most of the elements that are part of a Full installation but not Server Core are idle unless a user is logged onto the server. And because servers usually don't have users logged onto them except when they're being administered, the result is that the performances of a Server Core installation and a Full installation are about equal if they are both running identical roles.
So what are the benefits of running Server Core instead of a Full installation? There are many, including the following:
- Greater stability. Because a Server Core installation has fewer running processes and services than a Full installation, the overall stability of Server Core is greater. Fewer things can go wrong, and fewer settings can be configured incorrectly.
- Simplified management. Because there are fewer things to manage on a Server Core installation, it's easier to configure and support a Server Core installation than a Full one—once you get the hang of it.
- Reduced maintenance. Because Server Core has fewer binaries than a Full installation, there's less to maintain. For example, fewer hot fixes and security updates need to be applied to a Server Core installation. Microsoft analyzed the binaries included in Server Core and the patches released for Windows Server 2000 and Windows Server 2003 and found that if a Server Core installation option had been available for Windows Server 2000, approximately 60 percent of the patches required would have been eliminated, while for Windows Server 2003, about 40 percent of them would have.
- Reduced memory and disk requirements. A Server Core installation on x86 architecture, with no roles or optional components installed and running at idle, has a memory footprint of about 180 megabytes (MB), compared to about 310 MB for a similarly equipped Full installation of the same edition. Disk space needs differ even more—a base Server Core installation needs only about 1.6 gigabytes (GB) of disk space compared to 7.6 GB for an equivalent Full installation. Of course, that doesn't account for the paging files and disk space needed to archive old versions of binaries when software updates are applied. See Chapter 2 for more information concerning the hardware requirements for installing Server Core.
- Reduced attack surface. Because Server Core has fewer system services running on it than a Full installation does, there's less attack surface (that is, fewer possible vectors for malicious attacks on the server). This means that a Server Core installation is more secure than a similarly configured Full installation.
Possible Usage Scenarios
Consider again the nine server roles you can install on Server Core:
- AD DS
- AD LDS
- File Services
- Print Services
- Streaming Media Services
- Web Server (IIS)
This list of roles should immediately suggest some possible usage scenarios for Server Core within your organization. Here are some ways that you could use Server Core to make your network more secure, more reliable, easier to manage, and easier to maintain:
- Infrastructure servers. Domain controllers, DHCP servers, and DNS servers are the backbone of your network. Running these roles on Server Core can strengthen this backbone in every way.
- Branch office servers. Because Server Core installations are more secure and require fewer software updates than Full installations, they are ideal for use in remote locations, such as branch offices where you have few (or no) information technology (IT) staff and less physical security than at your head office location. For example, you might deploy a Server Core installation as a read-only domain controller with BitLocker for added security at a branch office.
- Server consolidation and testing. Because Hyper-V is a supported role on Server Core, you can use Server Core to consolidate multiple servers onto a single system while still keeping them isolated. This can help lower your TCO by reducing your hardware requirements and your power, cooling, and management costs. Server Core running Hyper-V also provides a convenient environment for deployment testing.
- Extending hardware life. Because Server Core has lower disk and memory requirements than Full installations, you may be able to get more life out of old systems. For example, when you need to upgrade your e-mail or database servers, those boxes could be moved down the line to become network infrastructure servers running Server Core.
What shouldn't you use Server Core for? The main thing to understand is that Server Core is intended to run only the nine server roles listed previously. Nothing else. In other words, Server Core can't be used as a platform for running server applications such as Exchange Server, Microsoft SQL Server, or third-party server applications like SAP. You also can't use it for running Microsoft Office System applications or Microsoft Office SharePoint Server. And you can't (or at least shouldn't) use it to run custom applications you've developed in-house. In short, Server Core is not an application hosting platform.
This doesn't mean you can't install some applications on Server Core—you can, provided the applications have no dependency on the GUI. For example, you can install many of the following types of server applications onto Server Core:
- Antivirus agents
- Backup agents
- System management agents
You'll learn more about installing applications on Server Core in Chapter 13. But that's about it as far as what else you can install on Server Core is concerned.
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