To continue with this question:
Should be Vmware vCenter server high available?
According to the response there even if vCenter is down HA will continue to work.
So, if my vCenter is a VM, using the express sql edition in the same VM, and that VM is hosted in the same cluster it manages (and the cluster is setup for HA): Am I correct to assume that if the host that hosts the vCenter goes down HA will vmotion the vCenter VM to another host and it will continue to function?
BTW: my environment is small, two ESXi 5.0 hosts, with about 50 VMs, using iSCSI shared storaged for everything.
Best Answer
The vCenter VM won't be migrated to the remaining host, it will be restarted on the remaining host, so no vMotion will occur. It's also dependent on the VM Restart Priority. If the VM Restart Priority for the vCenter VM is disabled then it won't be restarted on the remaining host. If the VM Restart Priority is set to anything but disabled then the vCenter VM will/should be restarted on the remaining host. Note that the VM Restart Priority is dependent upon the available resources on the remaining host and the Admission Control setting (with or without DRS) so you want to set the vCenter VM restart priority to high to ensure that it is started on the remaining host.
Also note that a vMotion doesn't occur for the VM's on a failed host. VMware HA restarts the VM's on the remining host, it does not migrate them (with vMotion) to the remaining host.
Have a read here for more information:
http://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp?topic=/com.vmware.vsphere.availability.doc_41/c_useha_works.html