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Can you help me with my software licensing question?

I've been doing lots of reading on the Hyper-V server from Microsoft, the enterprise edition comes with the rights to run 4 virtual machines included in the license. Somewhere I read on Microsoft's site that includes 25 CALs also (I can't find the exact page currently, there website can be amazingly frustrated for finding information).

Do these 25 CALs apply to EACH of the 4 guest VMs, so if I have a 25 person business and I use all 4 Server licenses on my Hyper-V server that I'm good to go, or would I actually need an additional 75 client licenses on top of the original 25?

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marked as duplicate by Scott Pack, voretaq7 Feb 11 '12 at 3:10

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3 Answers

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Windows Server may have CALs included if you buy a retail (box) or OEM (preinstalled) product, but volume-licensed editions have no CALs included. In the first case, different numbers of CALS are available for different prices, and these bundles are differentiated by part number.

You can use CALs in two licensing modes with respect to Windows Server.

  • Per-server: Each server has a number of CALs assigned to it, and so if client machine A connects to three servers that are each in per-server mode, that machine will use three CALs.
  • Per-device or per-user: Each device or user has a single CAL assigned to it, and it can connect to any number of Windows Server instances using that one CAL. With per-user licensing, 25 User CALs will allow 25 users to connect to any number of server machines from any number of client machines. With per-device licensing, 25 Device CALs will allow any number of users to connect to any number of servers from 25 devices.

You can mix per-device and per-user CALs in your organization to save money in some cases, but it is probably more trouble than it is worth. I have never found a reason to use per-server licensing in an organization with more than one Windows Server. I'm not sure if FPP and OEM bundled CALs are per-user or per-device, or if you get to choose.

To answer your specific questions: The 25 CALs apply to all of your physical and virtual machines if you use them in per-user or per-device mode, but you would need 100 licenses if you operated each virtual machine in per-server mode. (If the host was running Windows Server roles that clients connected to as well, then you would need a total of 125 CALs in per-server mode, but it sounds like you are using it solely as a VM host.)

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When you buy Windows Server Enterprise Edition though either the FPP or OEM channels, you get 25 CALs with each copy. If you buy through any of the volume licensing channels, then you have to buy your CALs separately.

Windows Server CALs can be counted three different ways.

  1. Each CAL licences one end-user (ie one human being) to access as many servers (within one organisation) as they choose ("per-user").
  2. Each CAL licences one end-user device (e.g. a desktop computer) to access as many servers within one organisation as the user or users on that computer wishes. ("per-device")
  3. The administrator assigns a number of CALs to each instance of Windows Server and configures the operating system with that number of CALs; the servers are then constrained to only allow that number of simultaneous connections. ("per-server")

To answer the specific question, put your licences in per-user mode* and you can have 25 users connecting to all five servers (the host, plus four virtual ones).

*When you install Windows, it asks whether it's in per-server mode or per-user/per-device; the distinction between per-user and per-device is effectively on-paper; you'll get asked when you get audited and if the answer changes between audits then Microsoft might get annoyed, but probably won't care in practice.

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According to Licensing Microsoft Windows Server 2008 to Run with Virtualization Technologies (Page 6):

Users and devices licensed with a CAL can access any instances (physical and virtual) running on any physical server.

The way I read that is that if you have 25 CAL's with your enterprise version, you get 25 CAL's for each of the 4 guest OS's too.

The link to the document says "Windows 2008", but the document itself refers to Windows Server 2003. That leads me to believe that they decided the same rules that applied to 2003 apply to 2008, including Hyper-V, but someone forgot to update the document.

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AdamB: You are confusing a statment about per-user or per-device licening with per-server licensing. The passage you quoted is just reiterating the per-user or per-device licensing terms; it does not grant any additional licenses on a server-by-server basis. –  Jay Michaud Jul 13 '09 at 15:50
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