It is unnecessary to zero out dynamically growing disks, because they only occupy disk space when they actually write data to disk, thereby erasing all the data still stored on the corresponding hard disk sectors. Fixed virtual disks already occupy the hard disk’s space before the virtual machine writes data on it. Therefore, if you don’t wipe out the data on the disk, it is possible to recover data that has been stored on the hard disk before the space was assigned to the VHD.

What I wasn’t previously aware of is that this is even possible if you move the VHD to another host. This is probably the main reason why such “low level formatting” is required for fixed VHDs. As opposed to hard disks, VHDs can easily be moved to other locations, where people who should not be able to access data from the original host might have access to it.

Of course, in most environments virtual machines are only moved to hosts where the same administrators are responsible. This is where the VHD tool comes in. You can use it to create VHDs without having to first bother with the time-consuming wiping of the corresponding hard disk space. It can also be used to convert and extend existing VHDs.

This is the VHD tool’s usage description:

VhdTool.exe /create <FileName> <Size> [/quiet] VhdTool.exe /convert <FileName> [/quiet] VhdTool.exe /extend <FileName> <NewSize> [/quiet]

Create: Creates a new fixed format VHD of size <Size>. WARNING – this function is admin only and bypasses file system security. The resulting VHD file will contain data which currently exists on the physical disk.

Convert: Converts an existing file to a fixed-format VHD. The existing file length, rounded up, will contain block data A VHD footer is appended to the current end of file.

Extend: Extends an existing fixed format VHD to a larger size <Size>. WARNING – this function is admin only and bypasses file system security. The resulting VHD file will contain data which currently exists on the physical disk.

VHD tool

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The free Vmdk2Vhd tool can help you convert a VHD image into VMDK format. Note that it is recommended to convert a big VMDK file to multiple 2GB VMDK spanned files first. Jérôme Laban has described some other issues you might encounter.

Converting the virtual disk alone is not the only problem you will face if you want to migrate virtual machines from a VMware ESX or VMware Server to Hyper-V. It is like moving a hard disk from one computer to another or using the same OS image on different hardware. Virtual machines are not that much different than physical computers. Thanks to Windows Vista’s and Server 2008’s new imaging capabilities, it should always be possible to move virtual machines from one virtualization environment to another.

It might also work with Windows Server 2003 and Windows XP, but I would recommend using a more professional tool to convert virtual machines with these operating systems. I have used Microsoft’s Virtual Machine Manager 2008 (VMM 2008) to convert VMware machines to Hyper-V and it has always worked reliably. VMM 2008 is not free, but you can download a 180-day trial. I suppose that’s enough time to convert all your VMware machines.

Have you migrated virtual machines from VMware to Hyper-V or Virtual Server? If so, it would be nice if you shared your experiences.

Vmdk2Vhd

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The most common problem with VHDs occurs when the disk of a virtual server is full. The nice thing about virtual disks is that they are quite easy to expand. I can’t help but wonder why Microsoft’s virtualization solutions haven’t integrated this option. In theory, this should be possible even while the server is running. After all, it is no problem to defragment the disk of a running server, so why shouldn’t it be possible to resize an online VHD?

In any case, VHD Resizer is free and easy to use. One thing to remember is that you have to shut down your virtual server first. All you have to do is to tell VHD Resizer the new size, and the name of the new virtual disk. VHD Resizer supports fixed disks (disks with an unchanging physical size) and dynamic disks (disks that grow dynamically). It seems as if the tool also supports conversion from dynamic to fixed disk types and vice-versa, but this didn’t work in my tests. Enlarging a VHD, however, worked fine.

VHD Resizer changes the size of the VHD, but not the size of the NTFS partition. Thus, if you access the VHD through a virtual machine, you just see a larger disk with additional unpartioned space. You have to use a partition management tool, like diskpart, to extend the partition. Only then can you make use of the full capacity of the virtual disk. Diskpart is a Windows command line tool.

Extending a partition with diskpart is very simple:

1. Launch diskpart on a command prompt.
2. Type “list volume.” This gives you the number of the volume that you want to extend.
3. Type “select volume volume-number.“
4. Type “extend.”

Note that Microsoft’s documentation for diskpart states that only the extension of data volumes is supported. System or boot volumes may be blocked from extension. Even so, during my test, I was able to extend a Windows 7 system volume without problems. Still, it might be safer to add the VHD to another virtual machine as a data volume and extend it there.

By the way, if you only want to enlarge a data volume, you don’t need VHD Resizer. Just create another virtual disk with the appropriate size for your virtual machine, and then copy all files to the new disk.

VHD Resizer

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I will discuss all seven downsides from my own perspective and share some of the experiences we have had with server virtualization.

1. Magnified physical failures

Imagine you have ten important servers running on one physical host and its RAID controller runs amok, wiping out all of your hard disks. Don’t say that this is not very likely, as we have already had two or three incidents from malfunctioning RAID controllers from well-known brands.

There are several ways to compensate for this downside. One is clustering, which certainly entails extra efforts. Another answer is to backup the virtual machines with a CDP (Continuous Data Protection) solution. If your physical server goes down, it is possible to restore all VMs quickly to another host. This solution implies that you have enough capacity left on another host. Thus, if your virtual infrastructure is well planned, physical failures may be less problematic. However, this means that you have to invest in redundant hardware, which more or less eliminates one of the alleged advantages of server virtualization.

2. Degraded performance

There is no doubt that virtualization requires extra hardware resources. The problem is that it is almost impossible to estimate in advance how many extra resources will be needed. I know that there are capacity planning guides and tools but from my experience every piece of software behaves differently in a virtualized environment. We have applications that are quite modest as long as they run on a physical server, but when they were virtualzed their resource requirement multiplied.

You can’t do much if you have such applications. In our case, we had no choice but leave them on physical servers. Hence, the only solution to this problem is to thoroughly test each application with the virtualization solution of your choice.

3. New skills

It sounds so easy – install a virtualization solution and then just deploy your servers as you are used to. Not really! Many things are different in a virtual environment. I will give you just one example. When we installed our first server virtualization solution, I instructed our administrators to test some of their servers in the virtual environment. After a week or so, an administrator told me that he could not test his server because there was no more RAM available on the host. I was quite surprised, as this server has enough capacity for 10 VMs.

When I logged on, only 3 VMs were actually running. What happened? Some of his fellow administrators had assigned the same amount of RAM to the virtual servers as their physical servers had required. It took me quite some time to convince them to change their working habits. When you buy a new physical server, it is common practice to equip this server with as much memory as your budget allows. This makes sense, as it takes time to order new memory modules and add them to the server. Even if you do not require it now, you will most likely require more RAM very soon.

Of course, this situation is different in a virtual environment. I assign blame to myself, as we should have discussed things in advance. I should have told the administrators that they first need to figure out how much RAM their servers really need using a performance monitoring tool. If their server requires more RAM later, it is not a big deal to assign more. I chose this simple example because it demonstrates that you have to do some rethinking when you work in a virtual environment. The fact that several administrators share one physical server causes problems that didn’t previously exist. Of course, it is also necessary to acquire many new technical skills.

4. Complex root cause analysis

Virtualizing a server certainly implies big changes to the whole system. A new layer of complexity is added and can cause new problems. However, the main difficulty is that if something doesn’t work as it is supposed to, it can require considerable extra efforts to find the cause of the problem. I have another example for this downside of server virtualization.

We installed a SUSE Linux server under Virtual Server 2005. Everything worked fine at first. But, then the admin reported that his SSH sessions often got disconnected. We had another Linux machine running on the same host which didn’t show this behavior, so we thought it must be a configuration problem on the Linux system. However, this skilled Linux administrator wasn’t able to find the problem’s cause. I then had the idea to move this virtual machine to another Virtual Server host – and the problem was gone. So did Virtual Server or Linux cause the problem? Well, I can’t tell you. We never figured it out.

5. New management tools

Virtualization also has advantages, such as easier migration, cloning or snapshots. However, you can only take advantage of these new capabilities if you have the proper tools. Often, the tools that come with a virtualization solution are not enough, only supporting basic management tasks. This means that you need additional utilities, which cost both money and time. I am not only talking about such tools as VMware Virtual Center or Microsoft Virtual Machine Manager (VMM).

Another important field is backup, or more precisely, disaster recovery. Of course, you can use your current backup software to secure your virtualized servers. However, one of the advantages of server virtualization is that disaster recovery becomes much easier and faster provided you have a backup solution that is able to perform live backups of the virtual machines and not just of the virtualized servers running in these VMs.

The problem lies in that there are no real standards when it comes to virtual server management. But, there are standards for server management in general. For example, there are many backup tools that allow you to secure your Windows, UNIX and Mac machines, but it is difficult to find a disaster recovery solution that supports all the various virtualization solutions out there. All in all, this means that your zoo of management tools will grow, meaning more work for you.

6. Virtual machine sprawl

Even though virtual server management can get quite complex, installing a new virtual machine is a piece of cake. You need a new server? Just clone your master image to a new VM and you are done within a few seconds. The problem is that the number of servers might grow faster than the number of admins who are supposed to manage them. It is good that even virtual servers have physical limits. As soon as you reach the limit of your virtual capacity, the virtual machine sprawl will naturally stop.

The number of servers in my department has grown significantly since we started working with server virtualization. As a matter of fact, quite a few of them exist only because it is so easy to create them in a virtual environment. Thus, you have to be very careful that you don’t waste the resources of virtual server hosts with unneeded virtual machines.

7. Virtual habits

I am not sure if I understand this argument in the Networkworld article:

Once IT organizations start to use virtualization, they can’t stop themselves, Coyle said.

Coyle is the Gartner analyst who is the source of the insights in the Networkworld article. He makes it sound like virtualization is a kind of addictive drug. Perhaps he meant that organizations that discovered the values of virtualization are prone to introducing virtualization technology in areas where it is better they stay physical. I also see this danger, and it is difficult to give advice on this subject. Sure, there are some general rules, such as don’t virtualize servers that have unpredictable resource requirements. However, I think that virtualization often causes problems in unforeseeable situations. Coyle gives the only possible advice here: “test, test, test.”

What are your experiences with server virtualization? Do you think that the downsides outweigh the benefits?

Articles in this series:

• Seven disadvantages of server virtualization
• Does server virtualization reduce costs? Part II – Power savings
• Does server virtualization reduce costs? Part I – Hardware expenses
• Does server virtualization reduce costs? Part III – Software and payroll costs

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Considering the fact that VMM 2007 was released in September 2007, VMM 2008 has quite a few interesting new features. Most prominently are its Hyper-V and VMware ESX support. I will probably blog about the new features in another post. Today, I am just sharing some experiences I had when I played a little with VMM 2008.

I was quite surprised about the message I got from the VMM 2008 setup: “Microsoft System Center Virtual Machine Manager 2008 is not supported on this operating system. For more information, see ‘Supported Operating Systems for Virtual Manager’ in Virtual Machine Setup Help.” Uh-huh my operating system (Windows Server 2003) is not supported? I like the cooperation with Novel Linux, but it isn’t that going a bit too far? No, seriously, VMM 2008 only runs on Windows Server 2008 64 bit. My first thought was, aha, they want to push their new server operating system a little. But then, why only for 64 bit? So my second thought was, MS has to release VMM 2008 as fast as possible and they don’t want to waste their time with Windows Server 2003 and 32 bit.

Installation of VMM 2008 under Windows Server 2008 is super easy. It is a typical “Next-Next-Next” installation. If you know VMM 2007, you will be able to work with the new version, immediately. The user interface looks pretty much the same. The only real new thing about the VMM 2008 Admin Console that attracted my attention was this PowerShell button “View Script”. If you perform an action in the GUI, the VMM Administration console will tell you how you could have done this with PowerShell. This is certainly very useful, not only for those who prefer to manage VMM on the command prompt, but particularly for those who have to write PowerShell scripts to automate certain tasks. It is a very easy way to learn about the specific VMM commands.

I added a Virtual Server 2005 R2 host to my VMM 2008 without any problems. My Virtual Server already had the VMM 2007 agent installed, so I told the wizard to “reassociate the agent Virtual Machine Manager”. This doesn’t replace the VMM 2007 agent with the new VMM 2008 agent. I played with the virtual machines and everything worked, properly. However, the manual says:

When you update Virtual Machine Manager (VMM), you must update the agents on all managed computers. To work properly, the version of the agents on managed computers and the VMM server must match.

So I guess, for a first look it is okay to work with the old agent. If you want to manage this host again with VMM 2007, you just have to remove this host with the VMM 2007 Administrator and add it again. However, this only works if you didn’t install the new agent yet. To install the VMM 2008 agent, you have to click on Managed Computers in the Administration View and then select the managed computers on which you want to update the agent. Then you click on “Update” in the Actions pane. If you want to manage this Virtual Server host again with VMM 2007, you have to uninstall the VMM 2008 agent manually via the Server 2008 Control Panel.

Next, I wanted to try the Hyper-V support. Since I had no other 64-bit-installation of Windows Server 2008 at hand, I stalled Hyper-V on the same machine as VMM 2008. In theory, this shouldn’t be a problem. Adding the Hyper-V host wasn’t a big deal. I only had to run this update first, to install Hyper-V RC. Only then VMM installed its agent and everything looked fine at first.

Unfortunately, VMM was complaining afterwards that it wasn’t able to connect to the Hyper-V host. The host properties signified that the VMM agent was running but Connection Status displayed “Not Responding”. I found this a bit strange since I just installed the agent and VMM and Hyper-V resided on the same physical server. I tried to create a virtual machine anyway, and to my surprise, it really worked. The only problem was that I wasn’t able to boot up the VM. The VMM’s Job log files didn’t give me any hints what went wrong. Only when I tried to launch the VM via the Hyper-V user interface was I able to figure out what went wrong: The hypervisor didn’t even run.

As it turned out, it was my fault. AMD-Virtualization was disabled in the BIOS and so the hypervisor could not start. What I find a bit disturbing is that VMM wasn’t able to give me any hints what went wrong. The Jobs log only told me that it “could not retrieve configuration data from the virtual machine host”. To be honest, I expected a bit more from a central management tool. Okay, this is just beta software. But, I doubt, somehow that the final will be better here.

Nevertheless, I like the user interface and the price of the tool. We purchased Virtual Machine Manager a while back even though I had a couple of problems with VMM 2007 in a test environment. I think together with Hyper-V, Virtual Machine Manager 2008 will be a very competitive virtualization solution. I suppose, I will blog about VMM 2008 again soon.

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I only played a little with Hyper-V, but I am already looking forward for the final to be released. At the moment we have two VMware Server 1.0 hosts and one Virtual Server 2005 machine. Both solutions work fine, but only for server applications that don’t need much performance. We tried a couple of more demanding applications, but those tests all failed. It is interesting to note that VMware Server was always slower than Virtual Server when Linux was the guest OS.

We have been considering buying VMware ESX, but in my view, it is too expensive. The main advantage of virtualization is to save costs, but in our environment it would get more expensive with VMware ESX. Even though, VMware certainly has the better product, I see hard times are coming for them as soon as Hyper-V is released. But who knows, maybe they will reduce their prices. VMware GSX once was quite expensive, too. I guess we will soon know what the lowest possible price for VMware ESX is.

We are planning to test Hyper-V soon to see if its performance is really better than with Virtual Server and VMware Server. I will then report about it here. Stay tuned!

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There are some new interesting features, but only one is really important for me. Unfortunately, it is a change for the worse. These are the new features:

• Web-based management interface
• Support for Vista, Windows Server 2008, Red Hat Enterprise Linux 5, Ubuntu 7.1 and others
• Support for 8GB RAM per virtual machine, up to two virtual SMP (vSMP) processors and up to 64 virtual machines per host.
• 64-bit guest operating system support (Intel EM64T VT-enabled processors and AMD64 processors with segmentation support)
• Support for VIX API 1.2 (a programming interface for automating virtual machine and guest operations)
• Support for Virtual Machine Interface (VMI): guest OS can run either on native hardware or in paravirtualized mode.
• Support for USB 2.0 devices

If you are regular reader of my blog, then you’d already know which of the new features really turned me off. Yes, it is VMware Infrastructure Web Access, the new Web-based management interface for VMware Server 2. I thought, Virtual Server’s admin console is the worst imaginable user interface, but VMware managed somehow to beat Microsoft here. At least, Microsoft recognized now that a Web browser is not really made for managing back-end apps. So they decided to give Hyper-V a real user interface.

So, what is so bad about this new user interface of VMware Server 2? First of all, it is sluggish as all web-interfaces (some of Google’s tools excluded). Second, do you really want to logon to a server using a console that is embedded in a browser window? VMware Server 1 has this nice autofit feature which automatically adjusts the screen resolution of the guest when you resize the console Window. It seems this is not possible anymore with VMware Server 2. At least I wasn’t able to find it and the documentation doesn’t contain the word “autofit”. I suppose, it is not that easy to program such a feature for a browser plug-in.

This browser plug-in is installed when you open the Console for the first time. It worked without problems on the host running Windows Server 2003 R2 SP2. But I wasn’t able to install it on a Vista machine. Under Firefox, I got the error message “Installation of msvcr71.dll failed. Error Code -202.” and with Internet Explorer I got a C++ Runtime Error. Later, I wasn’t even able to connect to Infrastructure Web Access with Internet Explorer. I guess it was an SSL-related problem because the last message I saw was a certificate error. Well, my test was over anyway since there is not much to explore with VMware Server 2.

I got a couple of other error messages, but I don’t want to bore you with them. Okay, this is just beta software. So you might expect to be confronted with some bugs. But I tested betas from VMware before and I never encountered as many problems. Many of them were in one way or another related to the web-interface.

The ugly user interface was not the only disappointment, though. The main reason why I want to move to Virtual Server 2005 R2 SP1 is its support for the Volume Shadow Copy Service (VSS). This allows you to run live backups of virtual machines. My hope was that VMware would offer VSS support for VMware Server 2. However, I am not sure if VMware plans to add such a feature in the final version. There is service called VMware VSS writer. I didn’t find anything about it in the documentation, though. So I wouldn’t count on it.

I just wished they didn’t mess up with the great management interface of VMware Server 1. Even if VMware Server 2 will support VSS, we will most likely move to Virtual Server now.

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The first thing I tried after I installed the tool is the snapshot feature. With VMRCPlus 1.5, I was able to create snapshots, but the recovery option was always grayed out. So I was pleased to see that after updating to version 1.6, I was allowed to recover a virtual machine. However, this feature still doesn’t work for me. All I got is this error message: Unhandled exception has occurred in your application (see screenshot). After that, the virtual machine was not even displayed anymore in VMRCplus. I had to add the virtual machine to make it visible again.

This snapshot feature was the only thing that didn’t work during my brief test. So I think VMRCPlus 1.6 is a good enough replacement for Virtual Server’s user interface. It is interesting to note that VMRCPlus can create snapshots while the guest system is online. Not even System Center Virtual Machine Manager (VMM), Microsoft’s more sophisticated management tool for Virtual Server, can do that. Well, at least, the snapshot feature (checkpoints), works there (most of the time).

What I like about VMRC 1.6 is that you can manage multiple Virtual Server hosts with one central interface. It is not so convenient as with VMM, though. All in all, it seems to me that Microsoft has to work a little harder to make its user interfaces for Virtual Server a bit more reliable.

Aaron Tiensivu summarized the new features:

1. To reflect the terminology used in the web administration UI of Virtual Server, the terminology of VMRCplus has been updated.
2. VMRCplus now offers configuration of scripts on both the Virtual Server and Virtual Machine level. This was missing from the previous release.
3. VMRCplus offers configuring promiscuous mode on the network so you can trace traffic in the virtual switch. This is something Virtual Server does not offer in the web administration UI.
4. Minor enhancements like storage of Console Manager coordinates, conflict handling when a shortcut already exists (something Virtual Server fails to resolve).
5. The COM and LPT port assignment logic has been fixed (most of it did not work).
6. The x86 installer package no longer installs on x64. This has been done to prevent issues with 32-bit VMRCplus on 64-bit Virtual Server.
7. Error handling has been enhanced and several issues have been fixed.

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In my first test, I realized that the VMM admin console was quite unstable. I assumed that those problems were related to the virtual environment where I tested VMM. For my second review, I just explored VMM’s features on a physical installation. I didn’t encounter any serious problems then. But the longer I work with VMM, the more troubles seem to arise. I am obviously not the only one struggling with VMM these days. Microsoft’s Technet forum is full of unanswered questions and bug reports.

Of course it is possible that my problems were caused by my own errors or that they were somehow related to some special conditions in my test environment. However, I installed VMM on a freshly installed Windows Server 2003 R2 SP2 system. I tested it with two new installed Virtual Server hosts. The whole installation and configuration of VMM is fairly simple. There is not much room for mistakes. And if an application crashes on a newly installed server, usually a bug is the culprit.

So here are the problems I encountered in my tests so far:

VMM Admin Console

I already mentioned it before. Virtual Machine Manager’s Admin Console is quite unstable. It completely crashed a couple of times. In some cases, I was able to reproduce the failure. When I tried to modify the hardware of a certain virtual machine the Admin Console would always shut down, improperly. This was independent from the location where I run the Admin Console. It crashed on the VMM server (Windows Server 2003 R2 SP2) and also on a Vista machine.

VMM service crashed

This happened only once. After one of the crashes of the VMM Admin Console I wasn’t able to reconnect to the VMM Server because its service was shut down, too. I had to restart it. The event log only contained a cryptic “Net Runtime 2.0 Error”. I didn’t try to find the cause of the problem since VMM seemed to work fine again afterwards.

Cloning Process

All in all, I cloned about 10 times. More than half of them failed in the first place. I cloned from host to host, and on the same host. Usually the cloning process would just be interrupted after a while. However, in all cases I was able to resume cloning using VMM’s repair feature. The error message always indicated that the connection to the Virtual Server host was broken. That was never the case, though. I always checked the connection immediately after the cloning process failed. I also ran some tests to make sure that there is no network problem.

Changing hardware configuration

This problem might be related to the cloning issue described above because it only happened with cloned virtual machines. Sometimes I wasn’t able to change the hardware configuration of a virtual machine. In those cases VMM always complained that the virtual machine has to be stopped first or that it is in safe mode. This was never the case, though. I wasn’t even able to mount an ISO image in those VMs using VMM. However, it always worked fine when I configured these problematic VMs with Virtual Server’s own admin interface. I concluded that it must be a VMM bug.

Access denied to virtual machine

After I updated one of these cloned VMs using the Virtual Server Admin Console, I was no more able to manage it with VMM. VMM would always complain with this message: Detailed Error (2910). (Access is denied (0×80070005)). So VMM didn’t have “appropriate permissions” to access this VM, anymore. However, all other VMs on this host were still manageable. The problematic VM also seemed to work fine. I didn’t encounter any problems when I managed this virtual machine using the Virtual Server admin interface. In the end I was able to configure it by using VMM’s repair feature again. It seems that this the most important feature.

Merging of checkpoints on a Linux guest system

Checkpoints are what VMware calls snapshots. They allow you to restore a virtual machine to a prior state. It is possible to merge several checkpoints to free hard disk space. When we tried this feature on a Linux guest system (SuSE Linux 10.0 Enterprise) a folder with all its contents was gone after the machine rebooted. The strange thing is that no checkpoint was created before or after this folder was added to the guest system. Only this one folder was deleted, everything that was added after this folder was created was still there. I suspect that VMM had problems with the large size of this folder (about 100 GB). Since then, I only use this checkpoint feature very cautiously.

There also were a couple of minor issues. The function didn’t work at first, but when I tried it again later, VMM recognized its mistake and allowed me to proceed. For example, I once wanted to shut down a virtual machine from the VMM Admin Console. VMM complained that this feature is only available if the Virtual Machine Additions are installed. After I reassured myself that they were running on the guest, VMM admitted its wrong assessment of the situation and let me shut down the VM.

There were other similar cases. I won’t list them all here. I think you got the picture by now. In my test VMM was quite unreliable. However in most cases I was able to get what I wanted in the end. I still like VMM because its user interface certainly is a major improvement to the old fashioned Web-based user interface of Virtual Server 2005. And of course VMM’s most interesting feature is its ability to manage multiple Virtual Server hosts with just one user interface. So at the moment I am undecided if we will work with Virtual Machine Manager in a productive environment.

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I first tried VMM under VMware Workstation, which probably doesn’t make much sense. This might have been just a bit too much virtualization. This time I installed Virtual Machine Manager on a physical machine running Windows Server 2003 R2 SP2. My test system just met the minimum requirements for VMM (Pentium with 2.8 GHz and 2GB RAM). Usually, one has to double Microsoft’s recommendations. However, I didn’t encounter performance problems. My test environment was quite simple, though. I just worked with two Virtual Server hosts, and 10 virtual machines.

When I played with the VMM under VMware Workstation, the Admin Console crashed several times. This didn’t happen in my new test environment. I installed the VMM Admin Console on my Vista desktop. The installation is easy and fast. The only information I had to enter was the name of the VMM server.

To use VMM, you don’t need a manual. Everything is absolutely self-explanatory if you have worked with virtualization software before. I only had problems with cloning virtual machines. It seems to be a bit unreliable. It failed twice after reaching 90% of the cloning progress. Virtual Machine Manager doesn’t allow you to clone while VMs are running. So basically it just has to copy the VHD files. I wonder what can go wrong here. The error message wasn’t helpful since it claimed that the connection to the host was lost which was not the case.

But in both cases I was able to get the new virtual machines working by using VMM’s “Repair Virtual Machine” feature. What I like about cloning is that you can use it to copy a VM from host to host. I tried this with Windows Server 2003 and Linux as guest OS. It is also possible to move VMs. This feature is called migration. Unfortunately, VMM doesn’t support live migration, that is, you can only move a VM if it is down.

You can also store VMs in the VMM library. This is useful if you don’t have enough space on your hosts and have to move offline VMs somewhere else, for example. So you can just park the VM on your VMM server in its library. Of course, you can’t run it there.

Very useful is VMM’s checkpoint feature. VMware calls them snapshots. Creating checkpoints allows you to restore a VM to a previous state. You can create multiple checkpoints of a VM. Unfortunately, this is also only possible when the VM is down. VMM shuts down the VM automatically, and restarts it after the checkpoint was created. In my test, this was done within a minute or so. The same applies when you restore a checkpoint. You can merge checkpoints if you need space on the host and if you are sure that you no longer need them. But VMM will also shut the virtual machine down then.

Microsoft really has to work on Virtual Server’s and Virtual Machine Manager’s live features. This is one of the major shortcomings compared with VMware products. Since this feature was also cut for Windows Server Virtualization (WSV), there is no hope that we will see an improvement in this direction in the near future. However, one also has to consider that with $499 for the Workgroup Edition, VMM is really cheap. You can only work with five hosts, though. If you have more Virtual Server hosts, you’ll need the Enterprise Edition which costs $860 per physical host (together with Operations Manager and DPM 2007).

VMM also supports physical to virtual migration (P2V). It is interesting to note that it is possible to migrate a physical server while it is online. However, you can also do this when the server is down by using the WAIK. The latter option is probably more reliable. I want to have a closer look at this feature, and I will report about it in another post.

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The hardware requirements are quite huge:

• Processor: Pentium 4 2.8 GHz
• RAM: 2 GB
• Hard disk (if using the default local SQL Server 2005 Express database instance): 7 GB
• Hard disk (if using a remote SQL Server database instance): 1 GB
• Hard disk (if using the VMM server as a library server): 80 GB

Notice that these are the hardware requirements from the SCVMM help file. Usually, one has to double Microsoft’s recommendations.

These are the software requirements:

• Windows Server 2003 SP1 or above (for VMM Server)
• .Net 2.0
• .Net 3.0
• SQL Server 2005 SP1 or SQL Server 2005 Express Edition (for VMM Server)
• WinRM (aka WS-Management v1.1)
• Windows PowerShell 1.0 (for VMM Administration Console)

If you want to test VMM under Windows Server 2003 R2 and enabled WinRM, then you have to disable it first and get it from the link above. I wonder why Microsoft didn’t include WinRM and PowerShell in the setup file like the other components.

There are three separate components to install: the Virtual Machine Manager Server, the VMM Administrator Console and the VMM Self-Service Portal. The Self-Service Portal is an optional Web-based management tool. Virtual Machine Server and Administrator Console can be installed on the same system. The Administrator Console also works under Windows XP and Windows Vista.

It is also required that the VMM server belongs to a Windows domain and you have to install WinRM on the machine where Virtual Server is running. This system has to be a Windows domain member, too. At least, I didn’t figure out how to connect to a standalone Virtual Server from SCVMM.

The Virtual Machine Manager Administration Console made a good impression to me. It is a bit like the one from ISA Server. You can use it to do many things where you would otherwise have to work with the ugly Web-based interface of Virtual Server. For example, you can start virtual machines, access them thru VMRC, save the state, clone VMs, and so on. Even though VMRCplus was already step in the right direction, the VMM Administration Console gets to be the first user interface for Virtual Server that earns this name.

Unfortunately, the Admin Console was quite unstable during my short test. It crashed a couple of times. Perhaps this was due to the fact that I tested it in a virtual environment under VMware Workstation 6. It could be that this was just a little too much virtualization. However, my virtual test server had enough resources available.

Since we are about to run some tests with Virtual Server anyway, I probably will have a closer look at SCVMM soon, assuming that I manage to get it running more reliably.

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MMC-based management console It seems Michael Otey, the author, already saw the new console. You won’t believe it, but WSV got a real graphical user interface, that is one which is based on Microsoft Management Console (MMC 3). I’ve been waiting for this a long time already. In my view, the web-based user interface of Virtual Server 2005 is the worst Microsoft ever made.

VHD format WSW will use Microsoft’s Virtual Hard Disk (VHD) format. This means that you still can use virtual machines that were created with Virtual Server 2005 and Virtual PC. That was expected.

Support for live backups using VSS (Volume Shadow Copy Service) Live backups of virtual machines is certainly a cool feature. However, that is already possible with Virtual Server 2005 R2 SP1 I can’t wait to try this feature with DPM 2007.

Guest clustering WSV supports clustering of virtual machines within the same node (shared SCSI adapter) or across different nodes (iSCSI or Fibre Channel SAN).

Host clustering Host clustering is probably more interesting than guest clustering. If your host crashes, all your VMs will be down, too. Otey writes that you can move all your VMs within 10 seconds to a backup node using this feature.

Snapshots The possibility of creating snapshots is certainly one of the advantages of virtualization since it allows you to go back to a stable state anytime you messed up your system. In a way Virtual Server 2005 supports this too, but I always found the Undo disk feature a bit complicated to use. Let’s hope that snapshot support of WSV is as easy-to-use as in VMware’s products.

32GB RAM per VM Virtual Server 2005 R2 only supports 3.6 GB memories per VM, which is not much indeed.

8-way virtual SMP per VM Virtual Server supports only a single processor per VM, with WSV you can have up to 8-way virtual SMP (symmetric multi-processing). This only works if the host has enough physical CPUs.

X64 and virtualization-enabled hardware I am not sure if this is considered a feature. WSV will only run on x64 hardware and the CPU has to support IntelVT or AMD Virtualization. Whereas it certainly makes sense to run VMs only on 64-bit hardware, it also means that WSV is restricted to new hardware.

Hypervisor-based architecture There is no doubt that this is the most interesting feature of WSV. Hypervisor-based architecture means that the virtualization software is not running on top of Windows like it is with Virtual Server or VMware Server. Instead WSV is directly running on the hardware which is comparable to VMware ESX Server. The main advantage of this architecture is better performance.

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You should have a fast Internet connection if you want to download the five rar files because they add up to 3 GB. Virtualization.info lists SCVMM’s most interesting features. The tight integration with Configuration Manager, Operations Manager, and Data Protection Manager sounds quite interesting.

I was surprised that the next version, SCVMM R2, will also support VMware and Xen. According to Sirrat, it should be available once Windows Server Virtualization (WSV) is released.

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According to Malone, Windows Server 2008 is feature complete now. This probably also means that the new hypervisor will really become part of the operating system even though the final of WSV supposedly will only be released within 180 days of the release of Windows Server 2008. Perilli is speculating that Microsoft is planning a hypervisor version for Vista. That could mean that WSV might not only replace Virtual Server 2005 but also Virtual PC 2007 in the long run.

I always wondered how the hypervisor will be integrated in Windows Server 2008. I read before that WSV will be just another server role. Although this seems to be true, adding the WSV role changes more than usual. It will transform the OS in hypervisor mode which means that Windows will be moved to the so-called parent partition.

This is comparable to VMware’s ESX Server. VMware just utilizes a version of Red Hat Linux instead of Windows. One advantage of WSV over ESX will be that the device driver support for Windows is a bit better. ESX will certainly have more advantages, especially because Microsoft dropped some very important WSV features (live migration capabilities, support for up to 32 processor cores, hot-adding of storage, networking hardware, memory, and processors).

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I am usually not so much into marketing texts, however this slogan could be useful if you ever try to get money from your boss for virtualization technology:

Welcome to the world of virtualization – where all of this is reality, and virtually anything is possible.

You can consider “all” as a variable that can be replaced with anything that comes to your mind in a real or virtual meeting with your boss. In the solutions section, you’ll find all Microsoft virtualization products: Softgrid, Virtual Server, Windows Storage Server / Data Protection Manager (?), Network Virtualization, Virtual PC, and Terminal Services (?).

I don’t understand why backup software like Data Protection Manager should be considered as a virtualization solution. And Terminal Services? If any system that allows multiple concurrent logons is a virtualization solution then our software world is much more virtualized than I thought.

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Some days ago, one of our admins who is responsible for our virtual servers was asking me if I know of a better way to backup virtual machines under VMware Server. At the moment, we shut down the VMs before we secure the virtual disk files. I replied to her, that I don’t know of a better option for VMware Server, but that we could consider moving to Microsoft’s Virtual Server once DPM 2007 becomes available. She was twisting her mouth then and said “Doesn’t Virtual Server have a web-based interface only?”

Only a day later I have read of VMRCplus. Of course, I was eager to test the tool. Installation was easy and fast. When I started it, the tool complained that I don’t have service pack 1 for Virtual Server installed. However, it worked anyway. To be sure, I updated my test server to Virtual Server 2005 R2 SP1.

VMRCplus consists of two tools, the Guest Manager and the Console Manager. The Guest Manager is for configuring Virtual Server, that is the virtual disks, the virtual networks etc., and for configuring the virtual machines. I was pleased to see that VMRCplus supports all settings of the web interface. At least, I found everything I was looking for.

You can start a Guest Console from the context menu of a virtual machine. If the VM is off, it will automatically boot up. Like with the VMRC tool that comes with Virtual Server, you can use the Guest Console to logon to the VM.

However, the console of VMRCplus offers some more options than the ultra simple VMRC tool. For example, you can mount CD/DVD drives, load ISO images, save states and access the guest’s hardware properties. You can also paste text you copied to the Windows clipboard on the host. The Guest Console has an extra menu point for this feature. So you can’t just use copy and paste directly to the guest system like with VMware Server and it is not possible to copy text from the guest to the host.

There are some more drawbacks. You can use VMRCplus to remotely manage a Virtual Server only if the host is in the same Windows domain as your desktop. It took me quite a while to figure this out because the error message just says “The virtual server service on server name does not exist or is unavailable or you may not have sufficient permissions to connect to Virtual Server”. Since I was able to connect to the same Virtual Server using VMRC, I thought it is just a configuration issue. Well, I should have checked the help file of VMRCplus earlier.

VMRCplus seems to support snapshots just like you know in VMware. However, this didn’t work in my test. I was able to create snapshots, but the sub menus of “Restore Snapshot” always stayed grayed out, regardless of whether the VM was on or off. It seems I am not the only one having this problem. Read the first comment in the weblog of VMRCplus’ creator.

The biggest problem with this tool however is that there is no official support. If you read the history of VMRCplus, you will recognize that this tool is just a hack of someone who was somewhat unsatisfied with the official interface of Virtual Server. (I can understand that very well.) So, the question is, how reliable is VMRCplus? During my test it happened once that my keyboard and mouse were blocked off while I was managing a guest system. I had to log off from the host to make it work again.

Please, check out Keith Combs’ Blahg for a complete feature list. All in all, I think, VMRCplus is a step in the right direction. However, Virtual Server still can’t compete with VMWare Server when it comes to usability. Thus, I hope that Microsoft will trash this ugly web-based interface in the near future and give us a full-blown MMC interface for Virtual Server. Otherwise, it will most likely be hard to convince our VMware admin to move to Microsoft’s virtualization solution.

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There is a fair chance that VMware might at least announce the release date of VMware Server 2.0. Since the current version number is just 1, it should be a major release. My biggest hope is that it will support VSS (Volume Shadow Copy Service) on Windows hosts. In my view, this is the only major advantage of Virtual Server 2005 R2 SP1 over VMware Server 1. Without VSS support for VMware Server, we will most likely move sooner or later to Microsoft’s Virtualization solution.

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Volume Shadow Service (VSS) Support: This allows you to perform live backups of virtual machines by creating snapshots. Microsoft Data Protection Manager 2007 will support such online backups of Virtual Server machines.

Support of AMD Virtualization Technology (AMD-V) and Intel Virtualization Technology (IVT): Essentially, this will improve performance. If you want to learn more about this topic, I recommend this Wikipedia article.

Offline VHD Mounting: You can now mount a VHD file even if the virtual machine is offline. This is useful for detecting and removing viruses and rootkits.

Active Directory integration: Virtual Server can now store its binding information as a Service Connection Point (SCP) in Active Directory. This enables you to search for Virtual Server installations in the forest.

Improved scalability for 64 bit hosts: x64-based hosts can now run up to 512 VMs using 256 GB memory. 32-bit hosts still only support up to 64 guests.

Host clustering: This feature is interesting if you have non-cluster-aware apps. You can improve the availability of those apps by clustering guest systems. Please, check out this new white paper for more information.

The most interesting feature is the VSS support, in my view. Until recently, live backups of virtual machines were a feature of expensive high-end virtualization solutions. We are still using VMware Server, but VSS support for Virtual Server might be a knock-down feature for us since we are also planning to use DPM 2007 as soon as the final is available.

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Virtual Server 2005 R2 SP1, mostly because of its VSS support, and Windows Server Virtualization certainly will change the virtualization landscape drastically. You probably know that WSV will become highly integrated with Windows Server Longhorn. I’ve been reading quite a few articles about it, but since I wasn’t able to test it myself it is hard to say what it will mean for Windows administrators. One thing is for sure, though, it will change a lot. Check out page 9 in this PowerPoint presentation if you want to get an idea how important virtualization will be in Longhorn Server.

By the way, it seems that the release date of Longhorn is approaching rapidly now. I’ve been asked to take part in a Microsoft workshop for journalists about Longhorn in Rome at the beginning of May. If Microsoft starts promoting a product this way, it usually means that the ship date is not too far away. It is probably only a matter of days until the Beta 3 will become available. So, I think, it’s time to get occupied with the next era in Windows administration.

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For me, a hypervisor was just a piece for software that runs directly on hardware partitioning CPUs, memory, etc. for guest operating systems. The only difference to a typical OS is that it runs other operating systems instead of applications. Well, I just learned that this only is half the truth.

Longhorn’s hypervisor still needs an instance of Windows Server running in the parent partition. However, Windows Server will run “on top” rather than underneath of the hypervisor. This basically seems to mean that the hypervisor just utilizes the device drivers of Windows Server. If I understand it right, then this is what is meant by the term “built-in-hypervisor“.

I also recommend reading the third comment of the article. An anonymous reader goes into more details there. If what “she” says is correct, then VMware ESX Server works in a similar way, just that it runs a light version of Red Hat Linux in the parent partition. This is similar to Longhorn’s hypervisor as it only needs Server Core which can also be considered as a light version of Windows Server Longhorn.

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