Virtualization Team

After installing or upgrading to VMware ESX 4, the Guest operating system’s memory usage might be overestimated on Intel systems that support EPT technology or AMD systems that support RVI technology. This issue might cause the memory alarms in vCenter to go off spuriously even if the guest is not actively accessing a lot of memory.

I have today visited another customer who had a problem that their virtual machines are always reporting a very high memory usage in vCenter while their OS task manager & TOP command in Linux machines were showing a very low memory usage. They did not face this problem before upgrading to vSphere which has made them unhappy with the upgrade. Fortunately, I was aware with this problem & was able to apply the magical VMware patch that has restored the customer happiness & confidence in VMware. The require VMware ESX 4.0 Patch was ESX400-200909401-BG: updates vmx and vmkernel64.

Many companies have always considered running Virtual Center in a virtual machine due to many advantages found below:

· Server Consolidation: instead of dedicating an entire physical server to VirtualCenter, you can run it in a virtual machine along with others on the same ESX Server host.
· Mobility: by encapsulating the VirtualCenter server in a virtual machine, you can transfer it from one host to another, enabling maintenance and other activities.
· Snapshots: A snapshot of the VirtualCenter virtual machine can be used for backup,
archiving, and other similar purposes.
· Availability: using VMware HA, you can provide high availability for the VirtualCenter server

One of the errors my customers repeatly complain about while upgrading to vCenter Server 4 or even when trying to install it from scratch is the following error:

“The DSN is pointing to an unsupported ODBC driver. Please re-configure your DSN to use one of the supported drivers.”

If you face this problem the first thing to do is to ensure that you are running a supported Database. Hint! Hint! SQL 2000 is no longer supported. If you are running SQL 2000 then you must upgrade to SQL 2005 or SQL 2008 before upgrading to vCenter Server 4.0

As a start don’t let the title fool you this is not related only to Microsoft virtualization, but to every virtualization platform out there. Don’t let vendors mislead you as the saving can be higher on Microsoft Licenses with non Microsoft Hyper-visor like VMware where you can put more virtual machines on the same hardware box. Ok, so clearing the confusion out of the way read below to find out what I am talking about.

Being on the consulting role, I get to meet customers everyday on all levels (Administrators, Managers, CEOs,  Directors, Business). When they ask our advice on consolidating their enviornment & I bring the idea of virtualization one question I get hammared with every time ” How would paying for virtualization licensing is going to save us money?”.  Below are some of our & yours traditional answers & how a stubrn customer will reply to it:

I have been contacted by Kevin Tolly the founder of http://CommonTestPlan.org to evaluate their Virtual Server Performance Test Plan & provide suggestions in that regard about two weeks ago. Kevin & his team were kind enough to provide me with a one year license to their Virtual Server Performance Test Plan Document for my own personal use without any string attached. I believe they are offering the same to many other Virtualization Experts around the globe in order to improve their document & get some honest feed backs from professionals who hit the virtualization field on daily basis. Below is my honest review & thoughts of the document.

I know I have been pushing back my vSphere exam for a while due to the amount of projects I am working on this year. I have finally passed my exam two days back with a blazing score of 494(haha thought it would be quite lower than this, but I guess the elimination process of answers that does not make sense had worked out very well on this one). I would love to thank everyone in the VMware community who had posted tips for the VCP exam especially Kumaran, Brian, Scott Vessey.  As my return to the community I have decided to post some tips for the exam:

As most of you already know VMware Storage VMotion is the ability to live migrate a virtual machine from one storage to another without any downtime. The usage most IT Professional relate to VMware Storage VMotion is the following:

The ability to move your virtual machines from a storage or datastore to another for maintenance reason or storage replacement without downtime. Though I had just came to discover another reason where it became vital. Thanks to Vladan as he brought it to my attention when he commented on my previous post:  VMware ESX 4 Reclaiming Thin Provisioned disk Unused Space

Disk Thin Provisioning & its ease of use in VMware vSphere has been one of the most used features. Although Thin provisioning has allowed customers to avoid allocating space upfront & saved them tons of space, it does not unallocate space when files are deleted from the Virtual Machine, this is due to the way Windows & other operating systems handle file deletion.

In many cases, the customer will create a Thin Provisioned disk with 80GB & use 10 GB out of it. At this time that Virtual Machine will only use 10 GB on the ESX host. Few days later, he might require to use another 50GB for a temporary purpose. Now he will have the Virtual Machine using 60 GB on the ESX host. After few days he go and delete the files that is occupying the temporary 50GB, then he will discover that the virtual machine does not shrink as he delete files from it & he still has a 50GB of wasted space.

Don’t get me wrong. I am happy with the current VMware CEO as well the VMware team as over all. My post is more of a message to the VMware Team & specially the CEO. I believe this below tip can help VMware crush the competition, though they have to study it carefully as it require a brave decision.

Since VMware started & it has been successfully gliding of the nice waves. It has always lead the competition by the quality of its product, as well the essential feature that no one else had. Although no one else had succeeded on over come the reliability & performance of VMware yet, many of the essential features has been replicated in many other Virtualization products in the market. Nonetheless VMware has always been able to innovate new features that customers will desire, customers started thinking that they could wait a year more and get this feature in a cheaper product, which has enough features for their current setup. Yes, I will spell it out many are looking at Hyper-v in this manner.

Before I start with the article, I have to point out this is not a VMware bug. Its the VMware admins doing what they are not suppose to do. VMware ESX 3 & VMware ESX 4 Administration Guides mention clearly that you should not VMotion or Storage vMotion a Virtual machine before disconnecting it from CD Media & ISO images that is only available to the first host or Datastore. Actually it will even warn you when you trying to do that.

I have seen tons of articles talking about the differences between VMware ESX & VMware ESXi, but I have not seen many that discuss when to use them. I have noticed that many of my customers get even more confused when reading comparisons between the two, as not all of them have deep understanding of the Virtualization Technology. That means they got to know the differences, but still wondering which one is best fit for their environments. Below is few rules that can put you on the right path.

I have a great news today from VMware. They have released the new version of VMware Site Recovery Manager SRM which will support VMware vSphere. This release of SRM had been long waited by many of us who upgraded, or already planning to upgrade to vSphere. I thought I will share the good news with every one.

The support for vSphere is not everything, but another great feature of the new SRM is the ability to support multiple source to a single target storage, which was not supported by earlier releases of VMware.

Another long waited feature for SRM is the support for NFS Datastores. Yes, finally NFS is supported by VMware Site Recovery Manager.

VMware seems to always come up with innovations that blow people mind. One of the latest VMware innovations I was checking out is VMware Mobile Virtualization.

Let’s see how VMware define Mobile Virtualization. As per VMware, Mobile Virtualization(MVP) is a thin layer of software that is embedded on a mobile phone to decouple the applications and data from the underlying hardware. It is optimized to run efficiently on low power consuming and memory constrained mobile phones. The MVP currently supports a wide range of real-time and rich operating systems including Windows CE 5.0 and 6.0, Linux 2.6.x, Symbian 9.x, eCos, µITRON NORTi and µC/OS-II.

As many VMware ESX monitoring tools are hitting the market place, and with the tend of these tools being dependent on SNMP (example: Starwind Free VM Monitor for VMware ESX), the more I am getting the question on how can I enable SNMP on my VMware ESX Server.. The instruction below will cover how to enable SNMP on VMware ESX (Note: VMware ESXi 3.5 does not support SNMP queries.).

To enable SNMP on VMware ESX Server 3.5:

1. Login to the console as root
2. Open snmpd.conf file with your favorite editor (Usually you can find snmpd.conf  in /etc/snmpd) and add “rocommunity xxxx” where xxxx is your read-only community string).

SolarWind has released a new VMware ESX Monitoring tool called VM Monitor. The new tool can monitor the status & utilizaiton of your ESX Servers as well your Virtual Machines. SolareWind VM Monitor uses the SNMP Service on VMware ESX to monitor your enviornment. As VMware ESXi does not support SNMP queries,  it’s still not supported by SolarWind VM Monitor. In order for SolarWind to work with your VMware ESX you will have to enable SNMP on your ESX hosts. A good instruction on enabling SNMP on VMware ESX Host can be found at: VMware ESX How to enable SNMP.

Below you will find a good video of the SolarWind VM Monitor in action, please note the video cover a bit of SolarWind Orion product which is not a free product.