We have rules on assigning and re-assigning and to fully understand the rights on Moving Instances we need to first fully clarify those rules
Assigning a license: To assign a license means simply to designate that license to one device. The purpose of this designation is to avoid sharing a license across multiple devices at the same time, once assigned a license, that server becomes the licensed device
Re-assigning a License: You may reassign a software license, but not on a short-term basis (i.e., not within 90 days of the last assignment). You may reassign a software license sooner if you retire the licensed server due to permanent hardware failure. If you reassign a license, the server to which you reassign the license becomes the new licensed server for that license.
Storing Instances: If a server is licensed, then stored or non-running instances of Windows Server and other Microsoft servers do not require separate licenses. The use rights permit you to store any number of instances under each license. You can also store instances on a large storage area network (SAN) or store instances on your servers without needing additional licenses for each instance.
Stored images can be shared and deployed across licensed devices
Some Virtualisation technology will dynamically move instances and this software will not take the license rules into consideration, so, from a compliance perspective, you need to keep a record of the "running" instances on each and every server, you also need to make sure you do not run an instance on a server box with no license assigned to it, as below
Windows Datacenter edition has UNLIMITED running OSE rights, so, if you license all your server boxes for Windows Datacenter, then you will not have to count the running OS instances or worry about running too many instances on a single server
Getting to Windows Datacenter edition
If you have Windows Standard Server or Windows Enterprise Edition AND Software Assurance coverage, you may "Step-Up" to Windows Datacentre edition for the price difference between the license and software assurance
Common Mistakes made with Virtualisation – All Incorrect
×One License = Unlimited Virtual Instances
×Windows server EE = 1 Host and 4 VMs which = 5VMs
×Dynamically assign license to devices running VM/Failover or move VMs to unlicensed devices
×Do not track how many VMs are “running”
×Do not license peak number of simultaneously running instances
Server Application Virtualisation next time……..