6.6

Figure 1- 3. vCenter Server Heartbeat Initiated Failover
When vCenter Server Heartbeat initiates a failover as a result of a failed application or service, vCenter Server
Heartbeat gracefully closes vCenter Server running on the active node and starts it on the passive node,
including the component or service that caused the failure. For example, if the Primary is active and the
Secondary is passive, the Primary is demoted to a passive role and is hidden from the network while the
Secondary is promoted to an active role and is made visible to the network. The mechanics of a failover are
discussed in more detail later in this guide.
Performance Protection
To ensure that vCenter Server is operational and providing service at an adequate level of performance to
meet user demands, vCenter Server Heartbeat employs the vCenter Server Heartbeat Plug-in which provides
performance monitoring and pre-emptive remediation capabilities. vCenter Server Heartbeat proactively monitors
system performance attributes and can notify the system administrator in the event of a problem and can also
be configured to take pre-emptive action to prevent an outage.
In addition to monitoring vCenter Server services, vCenter Server Heartbeat can monitor specific attributes to
ensure that they remain within normal operating ranges. Similar to application monitoring, various rules can
be configured to trigger specific corrective actions whenever these attributes fall outside of their respective
ranges. vCenter Server Heartbeat provides the ability to define and perform multiple corrective actions in the
event of problems on a service-by- service or even attribute-by-attribute basis.
Data Protection
All data files that users or vCenter Server requires in the application environment are protected and made
available should a failure occur. After installation, vCenter Server Heartbeat configures itself to protect files,
folders, and registry settings for vCenter Server on the active node by mirroring them in real time to the passive
node. If a failover occurs, all files protected on the failed (Primary) node are available to users after the failover,
hosted on the Secondary node.
vCenter Server Heartbeat intercepts all file system operations on the active node. Those write and update
operations which are part of the protected set are placed in the “Send Queue” of the active node pending
transmission to the passive node.
With the channel connected, the active node’s send queue is transferred to the passive node, which places
all the requests in the passive node’s “Receive Queue”. The passive node confirms the changes were logged
by sending the active node an acknowledgment. The active node then clears the data from its send queue.
The apply process running on the passive node applies all updates thereby creating a duplicate identical set
of file operations on the passive node.
VMware, Inc. 11
Chapter 1 Introduction