Server Reassignment Frequency

How often customers are allowed to move server software licenses between physical servers can depend on product version, product edition, and Software Assurance (SA) coverage status. The chart details the allowed reassignment frequency for versions of Microsoft’s six major server products released over the past decade. Reassignment frequency is of greatest relevance to customers who virtualize server workloads and require the flexibility to move virtual machines between servers on a frequent basis.

Either a license must be assigned to a physical server for at least 90 days before a customer can reassign it to a different physical server (middle column) or a license can be moved as often as necessary, but only between physical servers housed within the same server farm (right column). A server farm is defined by Microsoft as up to two data centers that are in time zones no more than four hours apart; licenses can be moved between servers in different server farms, but not more frequently than every 90 days.