Windows 2012 : Full or Core install ?

You maybe already noticed that Microsoft changed the default install mode of WS 2012 to core version ! What a change !

Where all Unix based server are proud to have black and white screen Microsoft ignored it since the beginning trying to build the most simple, fashion and powerful user interface. Moreover MS guys sometimes laugh at Unix admin considering them as old school guys using Vi, Emacs or other light and powerful tools

And today, in 2012, 19 years after Windows NT first release, we should install and use core version ! Why ? What happened ?

Well I don’t really know what is driving Microsoft in this direction but I just want to analyze Pro and cons and look at some figures.

First of all I installed two really default version of WS 2012 a full and a Core and here are the basic result of CPU, Memory and disk usage after install and without any utilization.

CPU
FULL
CORE
Memory
FULL
CORE
Disk
FULL
CORE

So if you install a core version you will basically save :

  • 3 process
  • 68 Thread
  • 137 MB of RAM
  • 2,87 GB of disk

You’ll also of course have less files on disk and less I/Os.

Ok ! this are the default figures. Now let’s see what Microsoft is telling us :

  • 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.

My Comment : That’s right. But how many times did your Win 2003 or 2008R2 crashed because of MS process ? The main process included in the full version of course is explorer.exe . This process sometimes crashed but on my PC when I have 20 windows opened, twelve applications and 5 VM running !

  • 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.

My Comment : This is my main point. I think they forget a point here, It’s easier IF you are a PowerShell expert ! How many of you are ?

  • 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.

My Comment : Ok, that’s true. Let’s see, if I take the last 6 month we have for each month from February to July  : 9 – 6 – 6 – 7  – 7 and 9 patches. What is your patching routine ? How many patches really need reboot ? How many patches will be applied to full and core ? and what is the difference between downloading 35 patch, install, reboot and download 5 patches, install, reboot ? Especially every 6 months …

  • 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.

My Comment : (these are Microsoft figures are for WS 2008) Right we saw that. You’ll save about 150 MB of RAM and 2,8 GB of Disk. If you have a huge infrastructure you may care about it.

  • 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.

My Comment : Have you ever be victim of a virus or pirate attack because of Windows GUI security vulnerability ? Yes ? so review your network security

Source : http://technet.microsoft.com/en-us/library/dd184076.aspx

Two other important things pointed by MS article, Core server will not improve performances and Core server are only eligible to :

  • AD DS
  • AD LDS
  • DNS
  • DHCP
  • File Services
  • Print Services
  • Streaming Media Services
  • Web Server (IIS)
  • Hyper-V

Ok, I seems to be a server core opponent but I’m not, in fact I’m loving it but in another way, let me explain.

My advise is the following, don’t install your WS2012 in core version, instead use the full version, configure your server, be able to manage it remotely and then after all test disable the GUI. Indeed, you’ll benefit from lower memory utilization, less process, lower security risks etc but not benefits from less disk pace usage because files for the GUI stay on the disk.

To remove the GUI use the GUI (to remove the GUI) or use the following PowerShell command :

Remove-WindowsFeature Server-GUI-Shell, Server-Gui-Mgmt-Infra

By doing that if one day you are not able to do something remotely or lost the server communication or whatever, go on the server and re-activate the GUI with the following PowerShell :

Add-WindowsFeature Server-GUI-Shell, Server-Gui-Mgmt-Infra

Enjoy

Julien

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