Information Technology Reference
In-Depth Information
Advanced Runtime Info exposes the vSphere HA calculations for slot size, total slots in
cluster, used slots, available slots, and failover slots. This is very useful information to
have. If you have Admission Control set to Enabled and aren't able to power on VMs that
you think you should be able to power on, checking this dialog box for the slot size might
reveal that the slot size is different than what you were expecting.
◆
Figure 7.27
h e vSphere HA
Summary tab
holds a wealth of
information about
vSphere HA and its
operation. h e cur-
rent vSphere
HA master, the
number of pro-
tected and unpro-
tected VMs, and the
datastores used for
heartbeating is all
found here.
Heartbeat Datastores Area
The Heartbeat Datastores area shows which datastores are currently being used by vSphere HA
for heartbeating. If you haven't explicitly dei ned which datastore can or should be used, this is
where you can tell which datastores were selected by vSphere HA for heartbeating.
Configuration Issues Area
In the Coni guration Issues area, vSphere HA will display any coni guration issues, for example,
if the cluster has exceeded the coni gured failover capacity. You might also see warnings about
management network redundancy (if the ESXi management network isn't redundant and pro-
tected against single points of failure). Based on the issues displayed here, you can take the
appropriate action to correct the problem or potential problem.
vSphere HA is a powerful feature, and we highly recommend its use in every vSphere imple-
mentation. However, vSphere HA does rely on restarting VMs in order to provide that level of
high availability. What if there are applications for which you need a higher level of availability?
vSphere offers that functionality with vSphere Fault Tolerance (FT). Based on VMware's vLock-
step technology, vSphere FT provides zero downtime, zero data loss, and continuous availability
for your applications.
That sounds pretty impressive, doesn't it? But how does it work? That's the focus of the next
section.
