Optional vCenter Server components are packaged and installed with the base product, but might require a separate license.
Optional vCenter Server features include:
- Enables you to move running virtual machines from one ESXi host to another ESXi host without service interruption. It requires licensing on both the source and target host. vCenter Server centrally coordinates all vMotion activities.
- Storage vMotion
- Allows you to move the disks and configuration file of a running virtual machine from one datastore to another without service interruption. It requires licensing on the virtual machine's host.
- vSphere HA
Enables a cluster with High Availability. If a host fails, all virtual machines that were running on the host are promptly restarted on different hosts in the same cluster.
When you enable the cluster for vSphere HA, you specify the number of hosts you want to be able to recover. If you specify the number of host failures allowed as 1, vSphere HA maintains enough capacity across the cluster to tolerate the failure of one host. All running virtual machines on that host can be restarted on remaining hosts. By default, you cannot turn on a virtual machine if doing so violates required failover capacity.
- vSphere DRS
Helps improve resource allocation and power consumption across all hosts and resource pools. vSphere DRS collects resource use information for all hosts and virtual machines in the cluster and gives recommendations (or migrates virtual machines) in one of two situations:
- Initial placement – When you power on a virtual machine in the cluster for the first time, DRS either places the virtual machine or makes a recommendation.
- Load balancing – DRS attempts to improve resource use across the cluster by performing automatic migrations of virtual machines (vMotion) or by providing a recommendation for virtual machine migrations.
vSphere DRS includes distributed power management (DPM) capabilities. When DPM is enabled, the system compares cluster-level and host-level capacity to the demands of virtual machines that are running in the cluster. Based on the results of the comparison, DPM recommends (or implements) actions that can reduce the power consumption of the cluster.
- Storage DRS
- Allows you to manage multiple datastores as a single resource, called a datastore cluster. A datastore cluster is an aggregation of multiple datastores into a single logical, load-balanced pool. You can treat the datastore cluster as a single flexible storage resource for resource management purposes. You can assign a virtual disk to a datastore cluster, and Storage DRS finds an appropriate datastore for it. The load balancer takes care of initial placement and future migrations based on workload measurements. Storage space balancing and I/O balancing minimize the risk of running out of space and the risk of I/O bottlenecks slowing the performance of virtual machines.
- vSphere Fault Tolerance
- vSphere Fault Tolerance provides continuous availability for virtual machines by creating and maintaining a Secondary VM that is identical to the Primary VM. This Secondary VM is continuously available to replace the Primary VM in a failover situation.