So you have your newly refurbished Dell Server – having been restored and rebirthed like a proverbial binary phoenix – primed and ready to go. All it needs now to fulfill your technological bidding: OS server software for Dell PowerEdge servers.

But what software can this puppy run?

Fortunately, Dell has released a pretty comprehensive whitepaper compatibility matrix for its PowerEdge Server line with Microsoft Server OS –link here. We’ll walk through some of the terms and terminology used, as well as give a little more background on server licensing in general and what exactly it all means in plain English.

You can see from the pdf matrix, that Dell quantifies levels of compatibility. In a nutshell:

• Qualified: this means that Dell tech’s have thoroughly tested the hardware and its compatibility with the Microsoft OS software and provide full technical support. It also includes Dell’s OpenManage support – you can read about it here, but basically, it provides some additional support for Server Admins.
• Supported: a more limited test certification which only includes the current release of the software.
• Blank: Not supported at all by Dell. That said – and we’ll get into this later – this doesn’t automatically mean that your Server cannot run a particular version of Server OS, it just means Dell engineers never tested to validate what level of support that could provide.
• Limited: the OS is only supported running in a guest OS or Virtual Machine (VM). We’ll talk a bit more about VM’s later, but you’ll notice that these instances are all under the ‘Legacy’ OS systems. See below…  

You’ll notice a big chunk of the Server OS versions – Server 2008 through 2005 – are listed are under the auspice of ‘Legacy Operating Systems.’

What’s important to know here is even though Dell’s engineers have tested the Microsoft OS releases on their servers, these versions are no longer supported by Microsoft. So while the server may successfully run the OS, don’t expect any new updates or patches. This means that if any security flaws are discovered in the software by bad actors, Microsoft won’t release any fixes. Not to mention, any third-party software tools you use on your server will also no longer be updated and supported because the OS itself is outdated.

Bottom line: it’s probably not a good idea to use legacy/unsupported OS on your server.

The latest versions of Windows Server OS – 2019 and 2016 – are noted with a ‘(LTSC)’:

LTSC = Long-Term Servicing Channel - this is just a fancy term for the standard release model of software that Microsoft has been following for a while. It means that Microsoft releases new versions of Windows Server every 2 to 3 years and your server OS software entitled to 5 years of mainstream support and 5 years of extended support.

Now, as an alternative, Microsoft offers a separate release model called Semi-Annual Channel (SAC), where releases come out twice a year. It’s only available to Microsoft’s volume-licensed customers with SA (Software Assurance; Microsoft’s paid service that allows for upgrades to the next release) but it basically give you access to more frequent releases; hence quicker access to the latest features of Server OS. It’s advanced techy stuff, but if that sounds like something that might fit your needs, you can read about it here.

The latest supported versions of Windows Server OS – 2012, 2013 and 2019 – come in three primary flavors:

• Datacenter: the most robust version for Enterprise-level functionality that allows for maximum virtualization. Core-based licensing.
• Standard: for a physical ‘boxed’ server or minimally virtualized environments. Core-based-licensing as well.
• Essentials: for physical servers with no VM’s. Designed for small businesses, 25 users, and 50 devices (capped). Processor-based. (PS, the word on the street is Microsoft is phasing out this version of Server OS to push people onto their O365 Office cloud solutions).

The above is a very general summary of what these versions do. As long as you get that Datacenter is for massive datacenters and lots of VM’s, Essentials is for a single, physical server hosting a capped number of users; and Standard is the middle ground between the two – that’s an excellent place to start.

NOTE: 2012 Foundations edition was retired/discontinued. The End of Support date for Windows Server 2012 is Oct. 10, 2023.

While we’re talking about virtualization, know that is a significant trend in IT right now: the act of creating multiple virtual instances – each running their OS as if they were a unique CPU – on a single server. It allows you to do so much more with less physical hardware and resources. It’s all a little heady, but here is an excellent article that explains it well.

Also, an important nuance to understand with server licensing is, as mentioned, DataCenter and Standard are core-licensing based; you must license a minimum of 8 core licenses for each physical processor and a minimum of 16 core licenses for each server.

Picking a random server from Dell’s PowerEdge product line, let’s look at R620 model.

Remember: anything blank is unsupported. Qualified is the highest level of certification, and Supported and Limited are defined at the beginning of the doc.

However, if we drill down within the 2016 release, things get a little nuanced. Notice that the Standard and DataCenter versions are checked – Qualified from the central product column – the Essentials Edition is not.

While DataCenter and Standard are indeed more robust versions of Server OS – remember, they are licensed by cores and not by Processor – as Essentials edition is. So while from a hardware perspective, the R620 could almost certainly run Server OS Essentials, the fact that it is a multi-processor with multi-cores makes it impractical to run this version of Server OS as you would need to license Essentials for each Processor. You get much more bang for your buck utilizing Server OS Standard.

Lastly, you’ll also notice for the R620 that is Qualified for Server 2016 but unsupported for 2019 (a handful of other servers fit this bill as well). Something to keep in mind is those servers likely ceased production shortly before 2019 – in the case of the R620, Dell lists the exact EOL (End of Life) on 5/25/2018. If Dell ended manufacturing the server in 2018, they probably aren’t going to have their engineers test the 2019 Server OS.

Bottom: there is a decent chance that the R620 – and other servers that are Qualified for Server 2016 – could run 2019 Server.

• Dell’s compatibility matrix whitepaper on Microsoft Server OS is a solid guide for determining what version of Microsoft Server OS is certified to run on your PowerEdge server. If it’s Qualified, you know a rigorous standard was applied to ensure compatibility.
• The caveats to keep in mind are Legacy (un-supported software) that while Dell has tested it as Qualified, Microsoft has ended support and updates for the OS.
• The other wildcard is even though a particular software version is listed as blank or unsupported, that doesn’t necessarily mean that the server is absolutely incompatible. It just means Dell’s engineers didn’t test it (remember, if they say it’s Qualified and supported, they darn well have to support it!). An excellent resource is to check the System Requirements for the Server OS you want to use – in the case of Server 2019, they can be found here. Even if your server fulfills the minimum specs, that doesn’t guarantee that the Server OS will work (other variables that can affect compatibility are drivers and firmware), but it can at least give you an educated idea.