6.4

Reference Guide
84 VMware, Inc.
Application Slowdown
Operations performed by the application can take longer to complete, and in turn, can affect the time required
to log in to a remote client, or to open or save a file. This is true for both servers running vCenter Server
Heartbeat and for servers running any other application. vCenter Server Heartbeat can monitor system
performance counters and display warnings when predefined thresholds are exceeded, but it does not actively
manage system resources for other applications. Like any other application, it also requires a finite amount of
resources for its own operations in addition to the resources used by the operating system and the protected
application.
The machines hosting vCenter Server Heartbeat must meet recommended hardware requirements and must
be powerful enough to support the load, the protected applications, and any other critical applications
running on the same server pair.
Poor Application Performance
When applications are competing for resources, one or more applications can perform poorly.
Symptom
Neither server in the pair can accommodate the load placed upon it during normal operation.
Cause
The Primary server's resource usage in one or more areas reached close to the maximum before vCenter Server
Heartbeat was installed.
Resolution
Heartbeat Diagnostics can report these conditions and issues warnings if CPU usage or memory usage exceed
a certain percentage of the available resource. Information provided by Heartbeat Diagnostics can minimize
the risk of application slowdown by identifying needed hardware upgrades on the Primary server.
Both Servers Can Accommodate the Initial Load but the Load Has Increased
Any software installed on a server or workstation consumes a finite amount of system resources when it runs
and it must share the resources it uses with any other applications running at the same time. Increased demand
caused by additional user activity can have an impact on the server performance.
Symptom
Increased user activity slows application response time.
Causes
The server pair operates normally when vCenter Server Heartbeat is first installed, but performance decreases
due to increased user activity. For example, users on the SQL Server system increase or the typical usage
pattern becomes more intense. This can be a gradual and sustained increase over time, or transient if a specific
event triggers a temporary surge in user activity.
Resolution
If the situation is sporadic, it can correct itself when the load decreases. If the increase is sustained and
permanent, upgrade the server hardware.
One Server Can Provide Adequate Resource Support, but the Other Cannot
If the total resource requirements of the applications exceed the available physical resources, the operating
system attempts to provide resources, but leaves some applications under resourced. When this situation
occurs, an application cannot obtain enough memory to operate normally, or a process must wait before
accessing the hard disk