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E-Guide

Expert tips for monitoring your

VMware environment

Traditional system performance monitoring tools cant access the

underlying virtualization layer and therefore provide unreliable results

in virtual environments. Fortunately, VMware vSphere has several

built-in tools to monitor and troubleshoot host and VM performance. In

this e-guide from SearchVMware.com, gain expert insight into the

existing performance monitoring tools in vSphere for optimal virtual

environment management. And discover five VMware administration

and management tips that will help you better manage your VMs andavoid common mistakes.

Sponsored By:
http://www.nimsoft.com/


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SearchVMware.com E-Guide

Expert tips for monitoring your VMware environment

Sponsored By: Page 2 of 13

E-Guide

Expert tips for monitoring your

VMware environment

Table of Contents

VMware vSphere's built-in performance monitoring tools

VMware administration and management: Five quick tips

Resources from Nimsoft, Inc.


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VMware vSphere's built-in performance monitoringtools

By Eric Siebert, Contributor, SearchVMware.com

Monitoring the performance of your VMware vSphere hosts and virtual machines (VMs) is

critical for several reasons: many VMs compete for host resources, resource bottlenecks are

not always obvious, and a single bottleneck can greatly affect performance in a negative

way. Without the right monitoring, reporting and alerting tools in place, busy administrators

can overlook these issues. In this tip, we outline the free performance monitoring tools

available in vSphere to help monitor an environment and take appropriate action.

Traditional system performance monitoring tools cannot access the underlying virtualization

layer and often provide unreliable results for a virtualized environment. Fortunately,

VMware vSphere has several built-in tools to monitor and troubleshoot host and VM

performance.

To effectively monitor your virtualized environment from every angle, you should monitor

the VM itself, the host, the networking traffic and the storage traffic. This approach also

provides true insight into the performance health of your virtual environment.

Using the Perfmon performance monitoring tool

Let's begin with how to monitor virtual machines. If your VMs run Windows, the built-in

Perfmon utility can monitor performance. Prior to the release of vSphere, it was not

recommended to use Perfmon on VMs. In prior versions of VMware, Perfmon was unaware

of the activity at the virtualization layer, particularly concerning CPU and memory use. But

now, vSphere has added counters specifically for Perfmon that track CPU and memory use

and provide more accurate measurement. This change enables you to use traditional

Windows Management Instrumentation monitoring tools to get more accurate information.These new counters are included in the VMware Tools package and are labeled "VM

Memory" and "VM Processor."


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While the new VM counters provide more information about performance inside a VM, it is

best to monitor performance outside a VM as well. To monitor performance outside a VM,

use the vSphere Client, which has a Performance tab for every object that you can select in

vCenter Server (see below). Objects may be data centers, clusters, hosts or VMs. Selecting

a different object displays different types of data. Selecting hosts or VMs provides the most

detailed performance data, such as information on CPU, memory, disk and network

statistics.

When you select the Performance tab, you have two views available: Overview and

Advanced. The Overview option presents a dashboard of key statistics, and the Advanced

view provides more detailed information. Clicking on Chart Options offers additional

counters that may not show by default.


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The Statistics Level setting, which is configured in vCenter Server's settings, controls the

number of counters for each category. In the vCenter Statistics setting, the default is level

1, which is the lowest level and provides only basic performance information on each

resource. The setting can be increased up to level 4, which provides the maximum

information possible.

Choosing level 4 reporting, however, can slow the performance of vCenter Server and

drastically increase the size of its database. Here's why: VCenter Server stores historical

performance data in its database and rolls up data from one time interval (i.e., a five-

minute interval) to the next (i.e., a 30-minute interval). A rollup then takes the average of

several readings for the first time interval to generate the second interval's value. So,

vCenter, for example, might sample performance every five minutes and store these values.

After 30 minutes, vCenter averages the previous six five-minute intervals and rolls them up

to calculate the 30-minute one.

As you might now conclude, recording detailed performance metrics for multiple hosts and

VMs can cause the database to become quite large. So unless you have to troubleshoot a

performance problem and need more detailed information, I recommend leaving the

Statistics Level at level 1; the default level provides plenty of useful information for

everyday use.


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Also note that while vCenter Server provides configurable performance statistic collections -

- you can view both real-time and historical statistics as far in the past as you desire --

historical data is severely limited for ESX and ESXi hosts that are notmanaged by vCenter

Server, (60 minutes for ESXi and 24 hours for ESX).

The esxtop and resxtop performance monitoring tools

Another key performance monitoring tool is the ESX service console utility esxtop. Its

remote version is called resxtop and is included with the vSphere command-line interface

and the VMware Management Assistant (vMA). While esxtop can be used only on ESX hosts,

resxtop can run remotely and connect to ESX and ESXi hosts.

Esxtop is a text-based utility that generates real-time advanced performance statistics for

all host resources. If you aren't familiar with esxtop's terminology, output and navigation,

however, you may encounter a learning curve. Esxtop navigation requires the use of single-

key commands that are not displayed on the screen. Still, you can access a list of available

commands by pressing the H or question-mark (?) keys.


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The default esxtop display shows CPU statistics. You can add fields by pressing the F key, or

switch to other resource views by pressing C (for CPU), N (for network), M (for memory), D

(for disk adapter), V (for disk VM), U (for disk device), or I (for interrupt).

When using esxtop, here's a tip: Expand your screen horizontally. Many fields that display

across the screen are hidden until you expand your screen's view.

Esxtop can be run in three modes: interactive, batch and replay. Interactive mode is the

default mode and allows you to view and change the data that is displayed on the screen.

Batch mode allows you to collect and save data over time to a file, which can then be

imported to Microsoft Excel or Windows Perfmon for review. Replay mode allows you to

replay a statistics collection period that can be recorded with the vm-support command. The

vm-support command allows you to specify a duration and interval to collect statistics which

can then be saved to a file.

Esxtop isn't an all-purpose tool, but when it comes to troubleshooting performance

problems, it's invaluable. It displays several advanced statistics that are not shown in the

vSphere Client.


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vCenter Server performance alarms

While periodic monitoring performance with the vSphere Client or esxtop is beneficial inseveral ways, neither the vSphere client nor esxtop alerts you to problems in your

environment as they happen. Fortunately, you can use vCenter Server alarms. These alarms

alert you when specific resource conditions exist. VMware Infrastructure 3 offered few and

unhelpful -- performance alarms. VMware vSphere offers many more than its predecessor,

and these alarms are also more useful because of the new Condition Length field that was

added to the alarm trigger (see image below).

The Condition Length field can eliminate false alarms by allowing you to specify the length

of time for which a condition must persist before an alert is triggered. When setting an

alarm for VM CPU usage (see image below), for example, it may not be a problem if a single

VM is at 100% CPU use for a few seconds. If this condition were to persist for more than

five minutes, however, it could indicate a problem. Condition Length allows you to receive

an alert after that five minutes has elapsed.


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There are many helpful alarms available for host and VM resource usage. I recommend

taking advantage of them so that you can quickly resolve issues that affect performance in

your environment.


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VMware administration and management: Fivequick tips

By Eric Siebert, Contributor, SearchVmare.com

VMware administration and management can be complicated and frustrating. But it's much

easier when you know the optimal way to handle virtual machines (VMs).

VMware administration and management requires not only technical expertise but also

problem-solving skills. And if you don't properly manage a VMware environment, it can

quickly come back to bite you. These VMware administration and management tips will help

you better manage your VMs and avoid common mistakes.

VMware administration tip No. 1: Thin is in

You should strive to properly size virtual disks, but sometimes disk size grows, such as with

a database server that accumulates additional data on a regular basis.

In these situations, administrators often allocate more disk space to a VM than is initially

needed. Thin provisioning helps reduce this wasted space.

Thin-provisioned disks do not allocate the full virtual disk size when created. Instead, they

grow as disk blocks are written inside the guest operating systems.

Thin provisioning can be done at both the virtualization and storage-array levels, so which

method should you choose? The answer is both. You get better space efficiency, and they

operate independently, so they will not conflict with each other. You can also use Storage

vMotion to re-shrink disks at the virtualization level when needed.

VMware administration tip No. 2: Install and update VMware Tools

Sure, VMs can run without VMware Tools installed inside the guest OS, but they won't run

as efficiently. Aside from its management tools, VMware Tools also contains virtual


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hardware drivers that are better optimized and more efficient than the default drivers in the

OS.

Additionally, VMware Tools enables communication between a hypervisor and the guest OS,

which helps optimize a guest OS to run on a virtual host. After you upgrade a host, keep

VMware Tools up to date. New versions may include new drivers and security enhancements

that are critical for optimum performance.

VMware administration tip No. 3: Monitor and limit VM snapshots

You should not rely on VM snapshots as a primary backup method. Snapshots are best for

ad hoc backups when performing OS and application maintenance and upgrades.

When snapshots are running, they have some resource overhead, which can limit feature

capabilities. They also create the potential for problems as your single virtual disk is split

into two or more virtual disk files.

It's best to delete snapshots as soon as you don't need them, because it's easy to forget

that snapshots are running, and you may not discover them until months later. At that

point, snapshots will have grown extremely large, and deleting them takes a long time,

which can cause poor VM performance.

Additionally, snapshots can eat up a lot of disk space on data stores. Therefore, you should

run periodic reports and use reporting and management tools and alarms to keep track of

this disk usage. The new Storage View in vCenter Server also has a snapshot size column,

which makes it easy to monitor snapshot usage.

VMware administration tip No. 4: Use templates and clones

The ability to create templates and clone VMs are big benefits of virtualization. Both actions

can make new VM deployments simple and easy.

Templates are standard VM images you can use to create new VMs with just a few clicks of

the mouse. Cloning, on the other hand, makes an identical copy of an existing VM, which is

useful for creating new VMs and troubleshooting.


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Both methods require vCenter Server, but there are other ways to duplicate this

functionality, including vCenter Converter, command-line tools and the vSphere Client.

VMware administration tip No.5: Deal with rogue VMs

Sometimes VMs go into a "zombie state" and can't be powered off. On a physical server,

you can yank the power cord to reset a hung server. But VMs don't have power cords, so

that's not an option. If you reboot the host to reset a VM, you'll disrupt the other VMs on

the host.

Fortunately there are some brute-force methods that you can use from the host's

management console to reset a VM without powering off the host. But these methods differ

for ESX- and ESXi-based hosts.


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Resources from Nimsoft, Inc

Best Practices for Monitoring VMware

Virtual Certainty: Best Practices for Gaining Monitoring Clarity in VMware

Environments

About Nimsoft, Inc

Nimsoft provides next generation performance and availability monitoring solutions for the

complete physical and virtualized IT infrastructure. The Nimsoft solutions redefine the

standards for ease of use and speed of deployment -providing outstanding return on

investment and unparalleled customer satisfaction. Over 680 customers in 30 countries rely

on Nimsoft solutions to monitor their IT based business applications and services. These

customers include mid-market and global organizations, such as Barclays Capital and

Amway Corporation, Bay Area Rapid Transit, Ladbrokes, MTU Aero Engines, TriNet, TRW

Automotive, and hundreds of leading managed service providers such as CDW Berbee,

Easynet and Rackspace Managed Hosting.
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