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In-Depth Information
event being logged by vCenter Server; whether the underlying condition has been resolved is
unknown. So, resetting the alarm to green just tells vCenter Server to act as if the condition has
been resolved. Of course, if the event occurs again, the alarm will be triggered again.
Now that we've looked at alarms for proactive performance monitoring, let's move on to
using vCenter Server's performance charts to view even more information about the behavior of
VMs and ESXi hosts in your vSphere environment.
Figure 13.7
For event-based
alarms, you also
have the option
to reset the alarm
status to green.
Working with Performance Charts
Alarms are a great tool for alerting administrators of specii c conditions or events, but they
don't provide the detailed information that administrators sometimes need, such as a resource
being used that is still under a warning or critical state. This is where vCenter Server's perfor-
mance charts come in. vCenter Server has many features for creating and analyzing charts.
Without these charts, analyzing the performance of a VM would be nearly impossible. Installing
agents inside a VM will not provide accurate details about the server's behavior or resource
consumption because a VM is coni gured with virtual devices. Only the VMkernel knows the
exact amount of resource consumption for any of those devices because it acts as the arbitrator
between the virtual hardware and the physical hardware. In most virtual environments, the
VM's virtual devices can outnumber the actual physical hardware devices, necessitating the
complex sharing and scheduling abilities in the VMkernel.
By clicking the Monitor
➢
Performance tab for a datacenter, cluster, host, or VM, you can
learn a wealth of information. Before you use these charts to help analyze resource consump-
tion, we need to talk about performance charts and legends. We'll start by covering the two dif-
ferent layouts available in performance charts: the Overview layout and the Advanced layout.
Overview Layout
The Overview layout is the default view when you access the Monitor
➢
Performance tab. Figure
13.8 shows you the Overview layout of the Performance tab for an ESXi host. Note the scroll
bars; there's a lot more information here than the vSphere Web Client can i t in a single screen.
