From the archive. Originally published on dailyhypervisor.com on June 13, 2014.

There are two types of vSphere reservation within vCAC. Reservations against a vSphere host and reservations against vSphere clusters. In order to create either a vCenter server is required. To make a reservation against a vSphere host it cannot be part of a vSphere cluster. Unlike physical reservations when creating a vSphere reservation you do not need to consume the entire vSphere host or Cluster in one reservation. You can create multiple reservations against a vSphere resoruce consuming parts of it in each reservation. You also have the ability to over subscribe the vSphere host or cluster.

When creating a vsphere reservation you have the ability to reserve memory, storage, and determine what networks are available within the reservation. vSphere reservation also give you the ability to determine how workloads can consume the resources. This is achieved in a number of ways. The first of which is a reservation priority. The reservation priority allows you some control over how you consume your resources. Let''s say you have two reservations assigned to a business group. If you wanted workloads to fully consume one before being placed against the other you would give the different priorities. The one you would want to fill first would be say a priority of 1,and the other would be a priority of 2. If you want to fill them equally you would give them the same priority. This will cause vCAC to round robin the placement of the workloads.

You can also implement the same types of placement priority for datastores within the reservation using the priorities you associate to each datastore.

Creating a vSphere reservation

1. Start by going to Infrastructure -> Reservations -> Reservations and from the “New Reservations” menu select Virtual then vSphere
2. On the New reservation screen screen there is a few fields you will need to fill out. First select the Compute resource you would like to create the resource against. Next select the tenant you would like to assign the reservation to as well as the business group within the tenant. Finally you must set a priority for the reservation.
4. Next on the resources tab you will select the amount of memory you want to reserve as well as the datastores you would like to reserve capacity capacity against along with the amount of disk space to reserve. You will also need to set a priority for each datastore you enable and reserve capacity against. Optionally you may also map the reservation to a vCenter resource pool.
6. Next on the network tab you can select the networks you would like to make available to the reservation. On this screen you also have the ability to assign a network profile to the selected network. For more information on network profiles please send the network profile tutorial.
8. Finally if you click on the alters tab and configure your desired thresholds and notification email address(es) and click ok to save the reservation.