238 CHAPTER 4 Creating Virtual Machines DISK TYPE DESCRIPTION Differencing disks are used in a wide number of situations. For example, Microsoft Learning uses the differencing disk concept to create all of the training machines used in the courses they deliver. In the case of a course requiring several machines working together, such as a Microsoft Windows SharePoint course, one parent disk is created with a core installation of Windows Server 2008 and multiple child disks are created with the required server roles such as one for Active Directory Domain Services, one for Exchange Server, one for SQL Server, one for SharePoint Server, and so on. When the entire environment runs, each server role boots from the core parent disk and then the child disks run to create the required environment. Because differencing disks are based on a single parent, performance can be very poor unless you run differencing disks on the fastest spindles you have access to. However, because of the parent-child relationship, differencing disks can save significant amounts of actual disk space because the parent disk is the disk that requires the largest amount of space and the child disks only store actual differences or changes made beyond the base parent disk. In the case of the MS Learning disk example, you can often create very complex environments with only a few gigabytes of used space. A parent can have multiple different and unrelated child disks such as in the case of installing different products on different child disks or it can have a hierarchical relationship to child disks, with each child becoming the parent of the next child disk as new child disks are created. The latter is what happens when you use the Hyper-V Snapshot feature because you automatically turn the existing VHD into a set of differencing disks. Each time you create a snapshot, you create a new parent-child relationship between the VHDs. Differencing disks are often best used in training, testing, or development environments because they always allow you to go back in time by breaking the parent-child relationship and return to a given state of the VM. The three disk types listed in Table 4-3 make up the different types of disks you will normally work with in Hyper-V (see Figure 4-10). More Info VIRTUAL HARD DISKS For more information on working with virtual hard disks, look up the screen cast Working with VHDs at http://go.techtarget.com/r/5927599/30819. Lesson 2: Working Virtual Hard Drives CHAPTER 4 239 Dynamically Expanding Fixed Size Differencing Legend Parent Disk Child Disk Allocated Disk Size Used Disk Space FIGURE 4-10 Hyper-V VHD types Update alert HOT ADD VHDS VHDs are now a standard part of Windows Server 2008 R2 and Windows 7. For example, when you add a new disk in Disk Manager, you can create, format and consume VHDs directly from the interface. Because of this, you can now dynamically add or remove VHDs to running VMs. Note however that VHDs must be tied to SCSI controllers to use this feature. You can also add or remove pass-through disks to running VMs so long as the disks are tied to SCSI controllers. Windows Server 2008 R2 and Windows 7 can also boot from VHDs making it easier to consume this powerful disk format directly from the OS. You can store any of the three VHD types on physical hard disk volumes that can be in either direct-attached storage (DAS), network-attached storage (NAS), or storage area network (SAN) in nature. However, you must store them on partitions that are formatted with NTFS. You cannot store Hyper-V VHDs in folders that use the Encrypting File System (EFS) because EFS is an encrypting system that is usually tied to particular users, and storing VHDs in user profiles does not make them highly available because they must run in a single user’s context. If security is an issue, you can store VHDs on partitions that use the BitLocker full drive encryption system. However, note that BitLocker adds some overhead to disk operations, which may impact VHD I/O operations and therefore virtual machine performance. Use BitLocker encryption only in highly secure environments or in environments where the possibility of theft 240 CHAPTER 4 Creating Virtual Machines is present. The latter could occur in remote sites or in branch office locations where access to host servers cannot be secured because of the lack of a lockable storage room for servers. Ideally, your VHDs will be stored on a high-speed shared storage container that is accessible by multiple Hyper-V hosts. Using this strategy ensures virtual machine fault tolerance because the VM can run on any of the hosts that have access to the shared storage LUN without having to actually duplicate or replicate the VHDs from one location to another. VHD replication can take considerable time because they can range in size from 40 to many hundreds of gigabytes. Note that the maximum size of a VHD in Hyper-V is almost 2 terabytes and is set at 2,040 GB. exaM tIp MAXIMUM VHD SIZE Remember that the maximum VHD size in Hyper-V is actually 8 GB short of 2 terabytes and is set to 2,040 GB instead of 2,048 GB. This item will definitely be in the questions you’ll find on the exam. Avoid running VHDs on system disks that are used to run the parent partition. Working with Pass-through Disks A fourth type of disk you can use in support of virtual machines in Hyper-V is the pass-through disk. Pass-through disks are physical disk partitions that are assigned to a virtual machine. Instead of using a virtual hard disk, you assign an actual physical partition to the VHD. Pass-through disks have the following features: n Performance Pass-through disks will give your VMs the utmost performance because Hyper-V does not need to manage the virtual disk during the operation of the virtual machine. When a VM runs, Hyper-V is only responsible for the actual operation of the VM and only needs to assign processor, memory, and networking resources to the VM. n Hybrid VMs When you use pass-through disks, you can create a hybrid VM using a VHD as the system disk and using pass-through disks for the data disks. For example, if you created a VM to host Exchange Mailbox Server, you might store the operating system on a small VHD tied to the IDE controller, then install all Exchange services on a second drive that is a pass-through disk. You could then assign additional pass-through disks for the messaging database and the transaction logs, ensuring the best performance for the Exchange Mailbox Service. n Pass-through Disk Connections Hyper-V VMs must boot from an IDE drive. Fortunately, you can assign a pass-through disk to a VM’s IDE controller. You can also assign pass-through disks to both SCSI and iSCSI controllers, but they must be for disks other than the boot or system disk. n Locked-in VMs Using pass-through disks locks the VM into the physical configuration you use to create it. The whole point of a virtual machine is that it is nothing but a set of files in a folder. When this is the case, you can create a VM in London, copy its files to New York, and then run the VM in New York. But when you use pass-through disks, you limit Lesson 2: Working Virtual Hard Drives CHAPTER 4 241 the VM’s mobility in much the same way you limit the mobility of a physical machine when you install an operating system physically. You must then find a way to move the contents of the physical disks the VM is composed of to another location to move the VM. To do this, you will often have to re-create the VM in its destination location or at the very least change its disk connections in the VM settings because they will no longer be the same. n Hybrid Pass-through Disks You can also create hybrid pass-through disks. For example, you cannot boot a VM from an iSCSI controller, but you can boot a VM from an IDE controller that is tied to an iSCSI pass-through disk. Here’s how: 1. Create a LUN in your shared storage container to host the boot and system partitions for the VM. 2. Use iSCSI to attach the LUN to the parent partition of a Hyper-V host. To avoid contention for the disk between the host and the VM, make sure the new LUN is offline on the host server. 3. Create your new VM and choose to create the disk drives that will run it after the VM is created. 4. Move to the VM’s settings and select IDE Controller 0 and Location 0 (In Use) and assign it to a Physical Hard Disk. Select the disk you attached through the iSCSI LUN. 5. Save your changes and boot the VM. The VM will boot from the iSCSI LUN. You can then install an operating system and run it from the iSCSI LUN. n Enlightened or Legacy Guests Both enlightened and legacy guest operating systems can use pass-through disks; however, legacy guests are limited to IDE functionality and cannot use SCSI pass-through disks. As you can see, pass-through disks can provide a viable option for several system configurations, but they limit VM functionality and do not give you access to any of the VHD capabilities that make VMs so much more exciting than physical machines. exaM tIp MAXIMUM PASS-THROUGH DISK SIZE Remember that the maximum pass-through disk size in a VM is limited only by the limitations of the operating system running in the VM, not by Hyper-V’s limitations. Using IDE or SCSI Disks When you attached disks to VMs, you must select how to attach the disk to the VM. Three possibilities exist: n Integrated Drive Electronics (IDE) When you attach a disk—either VHD or pass-through—to a VM through an IDE controller, you attach a virtual Advanced Technology Attachment (ATA) disk to the VM. You can attach up to four virtual IDE disks to a VM. Note that IDE controllers are created automatically when you create a VM. Both enlightened and legacy guest operating systems can use IDE controllers in Hyper-V. Also note that Hyper-V VMs must boot from a virtual IDE disk. 242 CHAPTER 4 Creating Virtual Machines n Small Computing System Interface (SCSI) When you attach a disk to a VM through the SCSI controller, you attach a virtual SCSI disk to the VM. However, because SCSI controllers are not created automatically during VM creation, you must create them after the VM has been generated through the New Machine Wizard in Hyper-V. This is done through the VM’s Settings dialog box under Add Hardware and then SCSI Controller. You can attach up to four SCSI controllers to a VM. Each SCSI controller can support 64 disks for a maximum of 256 virtual SCSI disks on a guest operating system. Note, however, that SCSI controllers are only available to enlightened guest operating systems that have Integration Services installed. exaM tIp LINUX INTEGRATION COMPONENTS Remember that LIC contain support for SCSI controllers just as the Integration Services do for Hyper-V–aware Windows guest operating systems, but do not include graphics drivers. n Internet SCSI (iSCSI) You can also attach disks directly to VMs through iSCSI initiators. For example, Windows Server 2008 includes the iSCSI initiator directly within the operating system. You can use this initiator to bypass the host operating system completely and expose a disk only to the VM it runs. You do this by loading the iSCSI initiator directly within the guest operating system and correctly configuring the target disk. The disk controller used in VMs does not have to correspond to the disk controller used in the host computer. For example, you can use Serial-Attached SCSI (SAS) devices on the host server and expose them as virtual IDE devices to VMs. You can also use both virtual IDE and virtual SCSI devices in a VM at the same time. However, because both devices are virtual and use the same optimizations in Hyper-V, their performance is similar even though IDE and SCSI performance in the physical realm is considerably different. Keep the following rules in mind when you work with disk controllers in Hyper-V VMs: n Use IDE only if you need four or fewer drives in the VM. n Use IDE to boot legacy VMs from VHDs or VMs that do not include Integration Services yet. n Use IDE and SCSI if your VM boots from a VHD, but you need more than four virtual drives in your VM. n Use pass-through disks to boot from iSCSI within the guest operating system. Make sure the disk is set to offline on the host’s parent partition. These guidelines will help you determine which method to use to connect a VM based on the requirements of that VM. More Info DISK CONNECTIONS IN VMs For more information on disk connections within VMs, look up Windows Server Hyper-V Storage at http://blogs.microsoft.co.il/blogs/dario/archive/2008/08/26/windows-server- 2008-hyper-v-storage.aspx. Lesson 2: Working Virtual Hard Drives CHAPTER 4 243 More Info iSCSI INITIATOR CONFIGURATION For instructions on how to perform iSCSI connections in Hyper-V, go to http://blogs.technet.com/josebda/archive/2009/01/31/step-by-step-using-the-microsoft- iscsi-software-target-with-hyper-v-standalone-full-vhd.aspx. For more information on iSCSI and Windows Server 2008, go to http://technet.microsoft.com/en-us/library/cc771740.aspx. Working with the Virtual Hard Disk Wizard Disk operations are performed through several different Hyper-V Manager interfaces. The first interface that gives you access to disk creation is the New Virtual Machine Wizard. Disk creation comes on the fifth page of this wizard, the Connect Virtual Hard Disk page (see Figure 4-11). The available options are: n Create A Virtual Hard Disk This lets you generate a new VHD. The VHD will be a dynamically expanding VHD by default. n Use An Existing Virtual Hard Disk This lets you connect to a previously created VHD. This VHD can be any of the three VHD types. n Attach A Virtual Hard Disk Later This lets you create the VM without a hard disk and attach it later by editing the VM’s settings. For example, you use this option when you want to connect the VM to a pass-through disk. FIGURE 4-11 Creating a VHD during VM creation VHD creation is performed through the New Hard Disk Wizard. This wizard gives you several options and lets you create disks in a wide variety of styles, choosing any one of the three VHD types (see Figure 4-12). The wizard can be accessed either through the Actions pane in Hyper-V Manager or through the VM Settings dialog box under the controller sections. 244 CHAPTER 4 Creating Virtual Machines FIGURE 4-12 Creating a new VHD If you choose a dynamically expanding or a fixed size disk, the wizard prompts you to name the disk, choose a location for it, and then identify the size of the disk to create. It also gives you the option to copy the contents of a physical hard drive into the newly created VHD (see Figure 4-13). In this case, the size of the disk will be the same size as the disk you are copying. FIGURE 4-13 Copying a physical disk into a new VHD Lesson 2: Working Virtual Hard Drives CHAPTER 4 245 If you choose to create a differencing disk in the New Virtual Disk Wizard, you will have to specify the location of the parent disk you want to use (see Figure 4-14). Remember that as soon as you identify a disk as a parent disk, it should be locked and used as read-only from that point on because if the parent disk changes, the parent-child relationship will be broken. FIGURE 4-14 Specifying the location of a parent disk for a new differencing VHD Another interface you can use to work with VHDs and pass-through disks is the Virtual Machine Settings dialog box (see Figure 4-15). In this case, you must begin by adding a new hard disk. You do this by selecting the controller you want to connect the disk to, choosing Hard Drive, and then choosing Add. After the hard drive has been connected to the controller—which can be either IDE or SCSI—you can configure the type of hard drive you want to connect. In this case you are given several choices: n You can control both the controller and the location the virtual hard disk will be connected to. n You can select the media type: • When you select Virtual hard disk (.vhd) file, you can either create the disk by clicking New or connect to an existing disk by either typing the path to the VHD file or clicking Browse to locate the existing VHD file. Clicking New launches the New Virtual Hard Disk Wizard. • When you select Physical hard disk, you must select the disk from a list of available partitions. Disks are listed as Disk 2, Disk 3, and so on. Disk 1 is usually assigned to the parent partition. Remember that the disk should be offline in the parent partition to avoid contention for disk reads and writes between the parent and the child partitions. 246 CHAPTER 4 Creating Virtual Machines n You can also use this interface to remove a disk from a VM’s configuration. Note that this does not delete the VHD from the host’s hard drives; it only removes the VHD from the VM’s configuration. FIGURE 4-15 Attaching disks to a VM You use the same interface to attach and create DVD drives to VMs (see Figure 4-16). This interface also gives you several options: n You can control both the controller and the location the DVD will be connected to. n You can select the media type: • New DVDs are connected to None by default. • You can also connect the media to an ISO image file. ISO is a special, non- proprietary archive format used to represent the integral contents of a hard drive, CD, or DVD. For example, many software vendors deliver their software products in ISO format. You can use a DVD creation tool or a tool such as WinImage to convert the ISO image into another medium such as a DVD, but vendors are relying on the ISO more and more because it is one of the best mediums for populating virtual machines. Lesson 2: Working Virtual Hard Drives CHAPTER 4 247 • You can connect the virtual DVD to the Physical CD/DVD drive. n You can also use this interface to remove a DVD from a VM’s configuration. FIGURE 4-16 Attaching a DVD to a VM More Info WINIMAGE Obtain WinImage from Gilles Volant Software at http://www.winimage.com. The VM Settings dialog box is also used to add or remove SCSI connectors to the VM’s configuration. In this case, you move to the Add Hardware option at the top of the left pane in the dialog box, select SCSI Controller, and click Add. As soon as you add the SCSI controller, the new SCSI controller is highlighted and you are given the option to add a hard drive to the VM’s configuration (see Figure 4-17). [...]... Tip Covered Exams Remember that since there are no Microsoft Press Training Kits for exams 7 0- 693: W ­ indows Server Virtualization Administrator or 7 0- 403: System Center Virtual Machine Manager 2008, Configuring, this guide attempts to perform triple duty by adding content in support of these exams along with the content for exam number 7 0- 652 Exam objectives in this chapter: n Manage templates, profile,... then use a physical deployment strategy to put the server in place Physical server d ­ eployments can easily take weeks, whereas virtual server deployment can take minutes (see Figure 5- 1 ) Week 1 Week 2 Before Virtualization Procure Hardware Configure Hardware With Virtualization Deploy from Template Week 3 Week 4 Week 5 Week 6 20 to 40 hrs of work 4- to 6-week lead time Install OS Configure OS and Tools... you can interact with the Server without having to open a Remote D ­ esktop Connection Table 5- 1 outlines the various supported operating systems for the ­ installation of the ­ dministrator Console A Table 5- 1   Supported Platforms for the SCVMM Console Platform Windows Server 2008 with Hyper-V x64 Standard, Enterprise, and Datacenter editions Windows Server 2008 without Hyper-V x64 Standard, Enterprise,... and run the pre-compaction tool on your hard drive before compacting it Obtain Virtual Server from Microsoft at http://technet.microsoft.com/en-us/evalcenter/bb738033.aspx Lesson 2: Working Virtual Hard Drives CHAPTER 4 251 Figure 4-2 0  Available actions for dynamically expanding VHDs Figure 4-2 1  Available actions for fixed size VHDs 2 52 CHAPTER 4 Creating Virtual Machines Figure 4-2 2  Available... The SCVMM user interface (UI) n The Hyper-V through SCVMM n The SCVMM add-ons Estimated lesson time: 35 minutes Working with Hyper-V Through SCVMM You installed SCVMM in Chapter 3, “Completing Resource Pool Configurations.” This is where you learned how powerful this tool could be to manage Hyper-V and other server virtualization hosts The central tool for host server management with SCVMM is the SCVMM... life to x86 physical machines or x64 machines whose processors do not include hardware-assisted virtualization because Virtual Server also runs on 32-bit o ­ perating systems When it runs on 64-bit systems, it does not have the same requirements as Hyper-V Remember, however, that Virtual Server can only create and run 32-bit VMs n VMwareViewer.exe  The engine used to open a remote connection to a VM running... Files\Microsoft System Center Virtual Machine Manager 2008\Bin” (see Figure 5- 5 ) Click OK twice You use the leading semi-colon to separate this folder from other folders in the path string; you use quotation marks because this folder name includes spaces Close all Control Panel windows 2 72 CHAPTER 5 Automating Virtual Machine Creation Figure 5- 5   Adding the SCVMM Bin folder to the path string The Bin folder... must use a non-Microsoft disk utility to replace the blank space in the VHD with zeros The zeros are then removed during compaction Virtual Server 20 05 R2 SP1 includes such a utility even though Hyper-V does not You can download Virtual Server, uncompress the Virtual Server files, and extract the PreCompact.ISO file from the Virtual Server installation files Then attach this file to your non-NTFS VHD and... Machine Remote Control command, use the following command (see Figure 5- 4 ): vmrc.exe /? Lesson 1: Exploring System Center Virtual Machine Manager CHAPTER 5 271 Figure 5- 4   Finding out more information on the Virtual Machine Remote Control command Exam Tip Managing Virtual Server Hosts One great advantage of being able to manage Virtual Server hosts with SCVMM is that you can give extended life to x86... Components to enhance Linux operating system performance when installed in Hyper-V child partitions n Hyper-V can run legacy guests such as DOS, Windows 3.x, Windows NT, and others Legacy virtual machines are older Windows operating systems or new non-Windows non-Hyper-V-aware operating systems n You must use the Hyper-V Input Release Key with a legacy guest operating system to exit from a Virtual . iSCSI connections in Hyper-V, go to http://blogs.technet.com/josebda/archive/2009/01/31/step-by-step-using-the-microsoft- iscsi-software-target-with-hyper-v-standalone-full-vhd.aspx. For more information. connections within VMs, look up Windows Server Hyper-V Storage at http://blogs.microsoft.co.il/blogs/dario/archive/2008/08/26/windows -server- 2008-hyper-v-storage.aspx. Lesson 2: Working Virtual. results of this inspection. The available options (see Figures 4-2 0 through 4-2 4, see pages 25 2-2 54 ) are outlined in Table 4-4 . TABLE 4-4 Edit VHD Options VHD TYPE OPTION DESCRIPTION Dynamically