vSphere components together with the required hardware setup and configuration form a VSA cluster.

A VSA cluster requires the following vSphere and vSphere Storage Appliance components:

ESXi 5.0 Hosts

Two or three hosts with new installation of ESXi 5.0 can join a VSA cluster.

vCenter Server 5.0

A physical or virtual machine that runs vCenter Server 5.0 and manages all ESXi hosts that participate in the VSA cluster. If the machine is a virtual machine, it must not run on an ESXi host within the VSA cluster.

vSphere Client 5.0

An interface that enables users to connect remotely to vCenter Server or ESXi from any Windows computer and to manage the VSA cluster from the VSA Manager tab.

vSphere Storage Appliance

A VMware virtual appliance that runs SUSE Linux Enterprise Server 11 SP1 and a set of storage clustering services that perform the following tasks:

Manage the storage capacity, performance, and data redundancy for the hard disks that are installed on the ESXi hosts

Expose the disks of a host over the network

Manage hardware and software failures within the VSA cluster

Manage the communication between all instances of vSphere Storage Appliance, and between each vSphere Storage Appliance and the VSA Manager

Only one vSphere Storage Appliance can run on an ESXi host at a time.

VSA Manager

A vCenter Server 5.0 extension that you install on a vCenter Server machine. After you install it, you can see the VSA Manager tab in the vSphere Client. You can use VSA Manager to perform the following tasks:

Deploy two or three vSphere Storage Appliance instances on two or three ESXi hosts to create a VSA cluster

Mount as datastores the volumes that each vSphere Storage Appliance exports

Monitor, maintain, and troubleshoot a VSA cluster

VSA Cluster Member

An ESXi host that runs a vSphere Storage Appliance. It is a functional member of a VSA cluster that exposes a datastore and maintains a datastore replica.

VSA Cluster Service

A Windows service that is installed with VSA Manager on the vCenter Server computer. The service is installed by default for all configurations, but is used in a VSA cluster with two members to act as a third member in case one of the VSA cluster members fails. In such a case, the Online status of two out of three members maintains the Online status of the cluster. The service does not provide storage volumes for the VSA datastores.


VSA datastores continue operating with I/O, even if the VSA cluster service stops working. However, simultaneous failure of one of the VSA cluster members and of the VSA cluster service results in failure of the VSA datastores, and the status of the cluster changes to Offline.

VSA Cluster Leader

A vSphere Storage Appliance that reports the status of the cluster to the VSA Manager. All members of the cluster participate in an election process through which they select the leader. The leader uses the cluster IP address to communicate with the VSA Manager.

Gigabit Ethernet Switches

Gigabit Ethernet switches provide the high-speed network backbone of the VSA cluster.