Standard license allows two “slots,” with each “slot” supporting a Windows Server
virtual machine), which would be cheaper than buying a Datacenter license. However,
complications will occur if you want to move virtual machines between hosts.
Consider Figure 1.9, which shows two Hyper-V hosts in a remote office that needs
only six virtual machines. The option shown in the example is using three copies of
Windows Server Standard on one server and a single copy on the other server, and this
is allowed. However, suppose you want to move the virtual machines to the other
server, as shown in Figure 1.10, to perform maintenance on the first server. This can
be done, but it requires moving two of the Windows Server Standard licenses between
physical hosts. License mobility allows the movement of licenses only every 90 days,
which means that you could move the virtual machines and the licenses, but you
would not be able to move the virtual machines back for 90 days.
Figure 1.9 Using stacked Standard licenses for virtual machines
Figure 1.10 Moving Standard licenses to enable licensed virtual machine migrations
To allow free movement of the virtual machines, the high watermark of virtual
machines ever present on the hosts would need to be used to calculate the required
number of licenses, which would therefore be three copies of Standard on both