Virtuozity

VMware has implemented some new features in the VMFS file system in vSphere 4 and these updates bring some good news for you: In the past you had to consider the block size very carefully when formatting a VMFS volume, because in VI3 configuration and log files were stored within the VMFS for the first time. This meant that every file allocated at least the chosen block size, no matter how large or small it really was. VMFS in vSphere 4 introduced the ability to store smaller files in so-called 64KB "sub-blocks" to save disk space.

So choosing a small block size will not give you an advantage anymore, it will only limit you in the future in case you want to grow your VMFS! Yes, that's another difference, you are not limited to extents in vSphere 4, now you able to really grow your VMFS, which makes it even more flexible. Unfortunately the VMFS wizard will still ask you to format your volume with 1MB block size by default. I would recommend to choose the largest available block size here to be as flexible as possible, because changing it later is not possible.

By the way, it is definitely false information that the chosen block size will impact your storage performance, but: Another highly acclaimed feature by VMware is thin provisioning. As you already figured out yourself, you should be pretty careful using it in your production environment, although there are cases in which it will be very useful. In my opinion thin provisioning also makes sense with larger VMFS block sizes, because increasing the VMDK file in tiny 1MB chunks doesn't look like best practice to me.

After some personal hard times I decided to continue this blog. To start off with something nice and easy, here are my favorite explanations for virtualization for non-techies... My thanks go to Eric Siebert for sharing these cool explanations with us!

Rob Bohmann: Virtualization is like a school bus. Instead of each parent driving their kid to school each day in their car with the resulting traffic jams and waste of time and fuel or having to build lots of extra lanes on the roads, we have the kids ride a big bus that can effectively carry a lot of people. We save resources like gas and space on the highways, as well as the parents’ time.

So if you substitute the energy of gas for the energy in electricity, whether derived from coal or nukes or hydro, etc., and the congestion around schools for the space in your data center and the more efficient management and provisioning of servers, I think the analogy works well, especially for people who are not in the technology arena.

Michael Nunn: Imagine you are a parent of four teenage daughters. All your life you have wanted to provide your daughters with their very own “resources,” like their own bedrooms, their own bathrooms, their own computers, their own clothes, etc., but you just could not afford to do it.

What if I could tell you how to give them all everything they wanted and they really believed that they each had their own bedrooms and bathrooms, but in reality you only had to build one bedroom and one bathroom? You would be well within your budget, your daughters would be very happy, and you would not be using space, materials and money to build all those separate rooms.

Mike Laverick: In the past, the server was a like a very expensive hotel. It was the worst kind of hotel. It only had one big room and only one person could stay there. However, all employees, whether they were the CEO or copy-boy, had to stay there if they were away on business.

This is like the guest operating system being installed to a physical server. Half the time the occupant is out doing other things, asleep, or just lying on the bed surfing up and down the channels looking for the type of channels his wife wouldn’t let him have at home. This is like when Linux or Windows is idling and only using 5% - 10% of CPU or memory. It became considered too costly to build such hotels and filling them with one occupant was very wasteful – because they consume heat, water and power – and most of the time the single occupant either wasn’t there or was asleep!

So someone had the idea of a better hotel, one which was divided into a series of different rooms. Each could be different sizes and offer different qualities of service. It didn’t matter what one guest did in one room, as it could not affect others. This hotel had really thick sound insulation so you couldn’t hear the wedding party downstairs or the newlyweds doing newlywed things next door.

On the top floor beyond the bridal suite, were the penthouse suites which were reserved for the high rollers, specifically for Mr. Exchange, Miss, SQL and Mrs. SAP – but in other floors the rooms were barely large enough to swing a small furry animal – this is where Mr. DHCP and Dr. DNS resided. The old hotel was so expensive only people like Howard Hughes could afford a room there – but this new, more efficient, hotel cost the same to build and maintain – and everyone could find a room that was suitable for their needs – from the odd billionaire to the business man on an overnight stay before catching a flight. It also meant we had to build fewer hotels.

The other thing we discovered was when Mr. Exchange or Miss SQL weren’t around or sleeping – as they were consuming less resources – their resources could be divvied out to the residents in the hotel to improve their experience. It would be easier to get that table in the fancy restaurant, and it was quicker to get served in the bar. Finally, the old hotel model died a swift and untimely death when the economy fell off the end of a cliff. It became increasingly regarded as a luxury no company could afford. The Hotel Virtualization model ruled the roost because it offered the most flexible model of accommodating guest operating systems with their wildly different resource demands.

The standard for Service Console (SC) RAM in ESX 3.5 server is 272MB. This minimum is fine for the standard server that does not have installed any other software. But you might have proprietary hardware agents, backup solutions or other software installed, and you might run into serious trouble you are unaware of, if do not expand the SC memory (e.g. HA agent errors). 512MB should be enough for most scenarios, but if you don't mind you can go for the maximum of 800MB. You have to configure the RAM size in the ESX configuration file

/etc/vmware/esx.conf

Just search for /boot/memSize = "272" and enter your value. After that you will have to deal with GRUB and the init process, because the settings are boot-relevant. ESX server has proprietary aliases for that, the command is esxcfg-boot. You have to run it twice: First time to regenerate the GRUB configuration files, the second time to recreate the initrd file with the new settings. You might want to use this short shell script, that does it all for you:

sed -i 's/memSize = "[0-9][0-9][0-9]"/memSize = "800"/' /etc/vmware/esx.conf
esxcfg-boot -g
esxcfg-boot -b

Because you have to reboot the host to take effect, so you should plan this for your next ESX patch day.

The VMware Update Manager is a very convenient way of updating your ESX hosts or your entire environment including VMs an their applications, but you have to configure it properly and sometimes even that is not enough. I recognized more than once, that no more updates were received for a while, but the Update Manager told me that everything was compliant although I knew it was not. So what to do?

First, please be sure NOT to use the old "VMware Infrastructure Update Client", an application which is still on your vCenter server for legacy reasons, but is definitely not the tool to update your ESX 3.5 hosts! The right way to do it, is to install the "VMware Update Manager Plugin" within your vCenter client application and activate it.

Now let us assume your Update Manager does not provide any more updates. Please uninstall the "VMware Update Manager" application and delete the remaining installation directory. Do not forget to delete the old download folder, because Update Manager keeps track of it's updates by a database and not by the files, and since we are going to reinitialize the database, you do not want any inconsistencies here. The standard path for Update Manager downloads is C:\Documents and Settings\All Users\Application Data\VMware\Data

Now you reinstall Update Manager from your ISO / DVD and enter credentials to access your proxy if you have one and the right DSN (ODBC connection). Please be sure the DSN is the correct one and that it is NOT your vCenter database, because when the installer asks if you want to reinitialize the Update Manager database, you select yes and confirm it.

After installing you open the vCenter client and check for the activated Update Manager plugin. You should have a new icon on the upper right, just click on it and configure your Update Manager properties, if you have to. Now click on "Scheduled Tasks" and you will see a now task named "VMware Update Manager Update Download". Reschedule it to suite your needs and if you want to do download the updates right now, just right-click on the task and run it.

Now let's talk about baselines: A baseline is nothing more than a list of available updates, divided into critical and non-critical updates for ESX hosts and VM guests. Update Manager compares your hosts and guests to these lists and looks for the delta. If your update repository is up to date and the delta is 0, the object is compliant. Otherwise there are one ore more updates available for the object. Please remember that you have to attach the baselines first, because NO baseline is attached after installation of Update Manager. To do that, go into the left pane and click on the object you are planning to remediate, e.g. "Hosts & Clusters" to update your whole environment. Now select the Update Manager tab in the right pane, click on "Attach Baseline" and select the ones you want to apply.

Now you should be ready to go, but remember that the first initialization could take very long because there are lots of update packages to download. Right-click on the object and first select to check for updates. Now the vcIntergrity component checks the objects for compliance. When the process is done, you are ready to remediate, again with a right-click on the object. You can remediate whole clusters because Update Manager only patches one host at a time. I strongly encourage you to test the patches in a non-productive environment first, because I experienced some cases where Update Manager continued with patching, even though something went wrong and the systems were not able to boot! So Update Manager shut down the whole cluster one by one...

If you do not want to update your Windows or Linux VMs with Update Manager, you should configure Update Manager skip those OS updates, because there are bags full of packages for these operating systems that will clog up your Internet connection. Most data centers have other methods for updating Windows and Linux, so if there is no need to do it, just don't do it. Click on the vCenter Update Manager configuration button and select "Update Downloads". On the right there is a small link named "Edit Update Downloads", where you can configure your Update Manager downloads.

If you have an Internet firewall with integrated anti-virus security, you might experience some problems downloading your update packages due to timeouts caused by the anti-virus scanning process. You can edit the vci-integrity.xml file in the Update Manager directory. Let's have a look at section downloadMgr, where you can edit

• maxDownload - How many downloads at once?
• downloadRetries - How many retries if a download fails?
• retryDelaySeconds - How many seconds to wait before retrying?
• recvTimeout - How long to wait before deciding a download has timed out?

The last entry is the one you can push up to solve the timeout problem with your firewall.

Link: http://www.vmware.com/support/vi3/doc/vi3_vc25u4_rel_notes.html

VMware released Update 4 for vCenter, which includes updates for all components. You can choose between English and new localized versions in Chinese, Japanese and German. I recommend staying with the non-localized version. Windows Server 2008 customization is available from now on, the rest are bug fixes. Please read the release notes to see all fixes, there are lots of.

The automatic update for the vCenter clients is disabled in this release, which is fine with me, because the feature did not work smoothly at all. So you have to update your clients conventionally.

There is a new optional JAVA-based "Performance Overview Plug-In", which you have to install manually. Please read the instructions, because you will need to install a JDK6 and add two environment variables before running the installer, and still the batch file did not run smoothly on our system. The new plugin will display a single view of key performance metrics for CPU, memory, disk, and network without navigating through multiple charts. From my point of view this implementation is absolutely no piece of art. Please, VMware, we do not need any more beta features, we need stable releases!