While limits and reservations make immediate sense to most administrators, shares are a more abstract concept, and although they have a major impact in the way that your workloads run on vSphere, these often get overlooked. Many administrators set these on resource pools and forget them later, but with dynamic workloads, the number of virtual machines in a resource pool can affect the distribution of shares and have negative effects on performance.

vSphere environments combine multiple classes of virtual machines. You might have first class, business class, and coach passengers if you'll allow an airline comparison. While you want your first class or mission critical virtual machines, to have all of the resources that they request, business class still get perks, but only after the first class virtual machines needs are met. Coach gets whatever is left over. Your development and test machines can be your coach passengers in vSphere.

If resource...