December 2006 - Posts

• The Most Evil Virtual Machine (as of now)

  Not everything that revolves around Virtualization is good - point in case: the software known as Microsoft.Windows.Vista.Local.Activation.Server-MelindaGates. This VMW virtual image fools Microsoft's latest operating system (Vista) into believing that it is contacting a Key Management Service server (KMS).  When Vista tries to access the KMS, it connects to the Virtual Machine and within seconds the operating system is activated and fully functional even though it is a pirated copy. As of now, Microsoft has yet to release an update that will fix this hack and assist Vista into knowing that it is not contacting a real KMS.  It really makes you wonder how soon the hackers will release and update to their VMWare image after Microsoft releases their update. The complete article is on on the vmblog's web site. Posted Dec 18 2006, 05:08 PM by Csaborio with no comments Filed under: Virtualization

• Convert VMWare Virtual Hard Disks to VHD Format

  Many people at Artinsoft use VMWare for their Virtualization needs.  This quickly became a hassle as the VMs that they were using that I needed could not be used in Virtual Server.  I just found out through this article that there is a new tool called the VMDK to VHD file converter. I have not yet tested the tool, but soon I will be converting all the RedHat VMDK to VHDs and running them on our Virtual Server R2 SP1 (which fully supports Linux!).  You can find the official link here, download it and let me know if you run into any issues! Posted Dec 14 2006, 11:44 AM by Csaborio with 2 comment(s) Filed under: Virtualization

• Should I use a SCSI or IDE controller for my VHDS?

  I have talked quite a bit in terms of the different VHDs there are, let's now focus on the different controller types that are available. When you create a VHD, you need to attach it to an emulated controller in order for the VM to use it.  You have two options: SCSI or IDE, but which one should you choose and why? The rule of thumb seems to be: if you can use SCSI, use SCSI, but why?  SCSI emulated controllers allow concurrent connections on the BUS, so this will make operations with multiple VHDs faster.  Furthermore, your VHDs can be bigger with SCSI controllers (2 Terabytes SCSI vs. 127 GB IDE!).  If that was not enough, SCSI controllers have more devices that can be attached to them.  IDE supports only 4 connections, SCSI supports up to 28! Furthermore, emulated devices such as DVD drives can only be attached to IDE buses, so you better save those buses for these types of connections.   So when should you use IDE controllers?  Use them when working with removable media or when you are dealing with a VHD that has an OS that will not allow itself to install itself on a SCSI connection. Posted Dec 14 2006, 11:36 AM by Csaborio with no comments Filed under: Virtualization

• Tidbits on VHDs - Part 2

  On my previous article, I touched base with the types of VHDs that are available.  I will now try and pinpoint which are the best scenarios to use each of those VHDs. Fixed disks are the ones that offer the best performance because there is no dynamic creation since the VHD is always the size that was specifed in its creation.  The chance of fragmentation is also less when working with Fixed VHDs.  If your application is disk intensive and you are planning on running it on a VM, then this type of disk is the best way to go. Dynamic disks work best when you want to make the best use of your space and you can withstand the performance penalty and fragmentation chance that can happen.  If you want to save the most space when running VHDs, then dynamic disks are your best option.  Use caution when working with dynamic disks as if the disk is expanding and the server runs out of space, disk corruption may occur. Differencing Disks are a blessing for the IT Pro.  If I was an IT admin, I would just have base VHDs of the most frequently used OS in my enterprise.  For instance, I would have various VHDs with Windows Server 2003 Enterprise, Windows XP, Windows Vista and so on.  When someone requested a Windows XP disk with Visual Stuido installed, I would just create a differencing disk and install Visual Studio.  You can also have differencing disks of differencing disks which can become more and more useful in the long run.  The main thing to watch out for is to make sure that the parent is always read only, since any modification will render the “son” VHDs in an unusable state. Finally, if you are looking for a way to convert a physical disk that does not contain an OS, you can just link the physical disk to a virtual one by setting up a Linked VHD.  Once you do that, all it takes is a trip to the Virtual Server Administrative interface and convert the linked disk to a fixed or dynamic one.  If you want to convert a physical disk that has an OS installed, you must use the Virtual Server Migration Toolkit.  Tips on how to use this tool belong in a future blog entry.  Take care! Posted Dec 01 2006, 04:24 PM by Csaborio with no comments

• Tidbits on VHDs - Part 1

  Virtual Server has various VHD (Virtual Hard Disks) available for creation, namely: Fixed Dynamic Differencing Linked In this first part of this blog, I will try and explain how each VHD works.  Fixed VHDs are the closest thing that resemble a real hard drive.  When you create them and specify its size to 20 GB for example, the actual VHD file will be indeed 20 GB in size.  This means that if you are only using 1 GB of the VHD, it will still be taking 19 GB of space on the server where the VHD is stored. Dynamic Disks, on the other hand, are not the size you specify at upon creation.  If you specify a dynamic VHD of size 20 GB, it will be originally created as a small drive, and as you write information and need more space, the VHD “dynamically” expands in size.  This operation can have a small toll on the VHD’s performance when it is expanded.  Furthermore, there can be more fragmentation issues since a sequence of bytes can be scattered in different places in the physical drive.  Differencing Disks have a parent VHD.  Only the difference between the parent and the son will be written to the differencing VHD.  This means that if you need to create 20 Windows XP machines, instead of creating 20 VHDs with Windows XP (something that could take 40 GB), what you can do is set a Windows XP VHD as the parent (2 GB) and set the 20 VHDs as differencing (around 200 MB per disk).  You will be saving a lot of space this way. Linked VHDs are pointers to real physical disks or partitions.  They are not meant to be used with virtual machines when they are on.  The only reason why you would want to use a linked disk is so that you can carry out a P2V (physical to virtual) migration.  In my next blog, I will talk about which VHDs work best for which scenarios. Posted Dec 01 2006, 04:12 PM by Csaborio with 1 comment(s)