Requirements and usage considerations
Virtual Machine Connection
These release notes address known issues about this RC1 release of Hyper-V™.
Requirements and usage considerations
This section describes the hardware and other requirements that apply to Hyper-V. It also describes usage considerations that apply to this release.
Hyper-V requires an x64-based processor, hardware-assisted virtualization, and hardware data execution protection. The Windows Server catalog, which can be found at the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkID=111228), lists systems that are certified for Windows Server 2008. Systems supporting the x64 architecture and supporting Hyper-V can be identified by the additional maker under the text “Certified for Windows”.
Configure the physical server as follows:
An installation of Windows Server® 2008 Standard, Windows Server® 2008 Enterprise, or Windows Server® 2008 Datacenter. You can install Hyper-V on either a full installation or a Server Core installation. To install Hyper-V on a Server Core installation, run the following command:
Start /w ocsetup Microsoft-Hyper-V
To manage Hyper-V on a Server Core installation, you can do the following:
Use Hyper-V Manager to connect to the Server Core installation remotely from a full installation of Windows Server 2008 on which the Hyper-V role is installed or from a full installation of Windows Vista® with Service Pack 1 (SP1) with the management tools installed. For more information, see Availability of the Windows Vista Service Pack 1 management tools for the Hyper-V release candidate (http://go.microsoft.com/fwlink/?LinkID=115100).
Use the WMI interface.
A maximum of 16 logical processors.
To limit the number of logical processors:
Click Start, click Run, and then type msconfig.
From the Boot tab, click Advanced options.
Configure the virtual machines as follows:
For the guest operating system, install one of the following:
Windows Server 2008 with Hyper-V, with a maximum of 4 virtual processors. No other release of Windows Server 2008 is supported with this release of Hyper-V.
The Windows Server 2003 operating system, with a maximum of 1 virtual processor for 64-bit and 2 virtual processors for 32-bit.
The following are the usage considerations for this release.
- Virtual machines that have dynamic volumes inside the guest operating system are supported for offline backup only when the guest operating system is configured to use dynamic disk in Disk Manager. When attempting a backup of such a virtual machine, it is saved and subsequently resumed, during the backup process. Even if the virtual machine is running, only an offline backup is taken. To avoid this issue, when using online backup, one should only use a basic disk. To fix this, either use offline backups or convert the dynamic disk to a basic disk.
- The data on the pass through disk attached to a virtual machine, or on the Internet SCSI (iSCSI) disk attached to the guest operating system will not be included in backup when a virtual machine has either a pass through disk or an iSCSI disk attached. To fix this issue, utilize backup agents inside the virtual machine and individually back up each virtual machine as if it is a physical computer.
- When attempting to attach an ISO file located on a network share to a virtual machine when both servers are in a workgroup environment, an incorrect error message is displayed: “The machine account 'User' does not have read access to file share '\\\\.iso'. Please add this machine account to the file share security. Error: 'General Access denied error' (0x80070005)”. To fix this issue, copy the ISO file locally.
- Virtual Machine Connection has a menu option under Clipboard to type clipboard text. This feature assumes that the source text is ASCII text in en-us locale as typed on a "QWERTY" keyboard layout. If non en-us or Unicode text resides in the clipboard buffer and the menu option is used, incorrect characters may be inputted into the virtual machine. There is no workaround or fix aside from using en-us text.
- If you use Authorization Manager to manage access to a server running Hyper-V and the authorization store is located in Active Directory, removing a user from a role assignment that controls access to Hyper-V functionality has no effect as the user will still be able to access Hyper-V. To remedy this, use XML for the authorization store or delete the role to which the user was assigned.
- If you try to restart or reset a virtual machine when the physical computer is low on available memory, the virtual machine may be turned off instead of restarted. To avoid this issue, retain at least 512 MB of memory for use only on the physical computer. To fix this issue, you can try to start the virtual machine. If this does not work, you can modify the virtual machine settings to reduce the amount of memory assigned to the virtual machine.
- If a clustered virtual machine has snapshots that reference non-clustered resources, they will not be detected. Trying to use the snapshots in question after failing over the virtual machine will result in the snapshots not starting. To avoid this issue, do not change resources between snapshots of virtual machines that will be clustered. Alternatively, you can ensure that all resources associated with all snapshots of the virtual machine are stored on the shared storage that clustering uses for the virtual machine. To fix this issue, manually copy the missing files or resources to the active node, or apply a snapshot that does not reference the missing resource and start the virtual machine from there.
- If you try to export a virtual machine to a network share where either the active user or the physical computer account do not have read/write access, the operation will fail. To fix this problem, grant read/write access for the active user and the physical computer account to the network share.
If you connect to a virtual machine on which the integration services are not installed, the mouse is displayed as a dot in the guest operating system. To resolve this issue, install the integration services if they are available for the guest operating system you want to use. To avoid this issue, use a supported operating system and install the integration services for that operating system.
- If you change the screen resolution while holding the mouse button down until the change is applied, all subsequent mouse clicks have no effect. To avoid this issue, release the mouse button before you apply a screen resolution change. To fix this issue, stop and restart the virtual machine.
- If you use Authorization Manager to manage access to a server running Hyper-V, be aware that all users who are authorized to view virtual machine output can view the screen thumbnail of a virtual machine in near-real-time without the knowledge of a user of that console. This is controlled by the Authorization Manager operation op_View_VM_Output and is configured for all members of the Administrators group by default. To avoid this issue, use Remote Desktop Connection to access the virtual machine. To fix this issue, configure that authorization so that only users who should be able to view sessions have the op_View_VM_Output operation capability.
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The following are the known issues for this release.
- If the Hyper-V authorization store is located in Active Directory (AD), then the removal of a user from a role does not take immediate effect. Either the Hyper-V server (hosting the Virtual Machine Management Service (VMMS)) or AD needs to be rebooted to percolate the changes. To avoid this issue, use an XML file as the store type. To fix this issue, reboot the Hyper-V server hosting VMMS, restart VMMS and Network Virtual Service Provider Windows Management Instrumentation (NVSPWMI) services or reboot AD.
When you open Hyper-V Manager for the first time, you must accept the end-user license agreement using an account that is a member of the local Administrators group. Otherwise, you will not be able to use the snap-in to perform any tasks. To avoid this issue, log on to the computer using an appropriate account before you open the snap-in for the first time. To fix this issue, close Hyper-V Manager, log on to the computer using an appropriate account, and then open Hyper-V Manager.
- Hyper-V update will fail when vmguest.iso is mounted by a virtual machine. To fix this issue, ensure that the ISO file is not being used by a virtual machine’s CD drive and reapply the update.
Virtual Machine Connection
- The use of Virtual Machine Connection within a Terminal Services session is not supported. To fix this behavior, close both Virtual Machine Connection and Remote Desktop Connection, and then run Virtual Machine Connection directly from the local computer. To avoid this behavior, do not run Virtual Machine Connection remotely.
If an authorized user is connected to a virtual machine via Virtual Machine Connection and another authorized user decides to use the console of the same virtual machine, the session will be taken over by the second user and the first user will lose the session. This can pose a privacy and security risk, because the second user will be able to view the first user's desktop, documents, and applications. A virtual machine session is available to all users who have been granted the Console Read or Console Read/Write operations privilege. By default, this is granted to any Administrator. To avoid or fix this issue, adjust the privileges to restrict access as appropriate.
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