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VMware, Inc. 17
Chapter 1 Introduction
This enables the public identity of the server. The active and passive servers both use the same system
name and same Principal (Public) IP address. This Principal (Public) IP address can be enabled only on
one system at anytime. When the public identity is enabled, any clients previously connected to the server
before the automatic failover are able to reconnect.
3 Start intercepting updates to protected data. Any updates to the protected data are saved in the send
queue on the local server.
4 Start all protected applications. The applications use the replicated application data to recover, and then
accept re-connections from any clients. Any updates that the applications make to the protected data are
intercepted and logged.
At this point, the originally active server is offline and the originally passive server is filling the active role
and is running the protected applications. Any updates that completed before the failover are retained.
Application clients can reconnect to the application and continue running as before.
Managed Failover
Managed failover is similar to automatic failover in that the passive server automatically determines that the
active server has failed and can warn the system administrator about the failure; but no failover actually occurs
until the system administrator manually triggers this operation.
Automatic Switchover and Failover in a WAN Environment
Automatic switchover and failover in a WAN environment differ from a automatic switchover and failover in
a LAN environment due to the nature of the WAN connection. In a WAN environment, automatic switchover
and failover are disabled by default in the event that the WAN connection is lost.
Should a condition arise that would normally trigger an automatic switchover or failover, the administrator
will receive vCenter Server Heartbeat alerts. The administrator must manually click the Make Active button
on the Server: Summary page of the vCenter Server Heartbeat Console to allow the roles of the servers to
switch over the WAN.
To enable Automatic Switchover in a WAN
1 In the vCenter Server Heartbeat Console, click the Network tab to display the Network Monitoring page.
2Click Configure Auto-switchover.
3 Select the Auto-switchover if client network connectivity lost for check box.
4 Configure the number of pings to wait before performing the auto-switchover.
5Click OK.
Recovery from a Failover
Assuming that the Primary server was active and the Secondary server was passive before the failover, after
the failover the Secondary server is active and the Primary server is passive.
After rectifying the problem that initiated the failover, it is a simple process to reinstate the Primary server as
the active server and the Secondary server as the passive server.
When vCenter Server Heartbeat starts on the failed Primary server, it detects that it did not stop cleanly the
previous time. It disables the public identity by deploying the IP packet filter and halts vCenter Server
Heartbeat so that the issues that caused the failure can be resolved.
N
OTE When failover conditions such as a power failure cause both active and passive servers to fail, the
condition may result that causes both servers to restart in passive mode. In this situation, manual intervention
is required.