Hyper-V Beta Release Notes

These release notes address known issues about this Beta release of Hyper-V™.

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 following hardware has been tested extensively and is suitable for use with Hyper-V. The most recent version of the BIOS is required. This list does not imply support of the platform for Hyper-V by the respective vendors.

The additional hardware listed below has been tested and reported as being suitable for use with Hyper-V by the respective vendors. By no means does the list below imply any support commitment by Microsoft or the manufacturer. In addition, the list below does not imply that the listed hardware will be supported with Hyper-V at final release. The most current BIOS revision is required for all systems listed below.

Configure the physical server as follows:

• An installation of Windows Server® 2008 Standard, Windows Server® 2008 Enterprise, or Windows Server® 2008 Datacenter, en-us Locale only. 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.
  • Use the WMI interface.
• A maximum of 16 logical processors.
  To limit the number of logical processors:
  1. Click Start, click Run, and then type msconfig.
  2. From the Boot tab, click Advanced options.
  3. Check Number of processors and then specify no more than 8 processors.

Configure the virtual machines as follows:

• For the guest operating system, install one of the following:
  • Windows Server 2008 RC1 with Hyper-V Beta, 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. You can install either a 32-bit version or an x64-based version.
• Maximum of 64 GB memory.
• Maximum of four virtual SCSI controllers per virtual machine.
• Maximum of eight virtual network adapters per virtual machine.
• Maximum of four legacy virtual network adapters per virtual machine.

The following are the usage considerations for this release.

• 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.
• The use of Virtual Machine Connection within a Terminal Services session is not supported. This type of usage can result in unpredictable mouse behavior and keyboard behavior. 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 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 because the user will still be able to access Hyper-V. To avoid this issue, use XML file as the store type. To fix this issue, use XML for the authorization store or delete the role to which the user was assigned.
• 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.
• 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 you import or export a virtual machine in a saved state or with snapshots, the network settings will be misconfigured in the snapshots or saved states. When you try to restore the virtual machine from a saved state or snapshot, you will receive an error message that the virtual machine cannot be started because the network has been misconfigured. To avoid this issue, delete all snapshots and saved states before you export the virtual machine. To fix this issue, modify the virtual machine settings to reconnect the network adapter.
• Online backup of dynamic disks with spanned, mirrored, or stripped volumes is not supported. If you perform an online backup when a virtual machine has one or more dynamic disks with spanned, mirrored, or stripped volumes, or when both the virtual machine and the physical computer have dynamic disks, the backup will fail or the disk will show up as a foreign disk. To avoid this issue, place the virtual machine into a saved state and perform an offline backup. To fix the issue of the disk showing up as a foreign disk, use Disk Management to import the disk and then bring it online.
• 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.

The following are the known issues for this release.

• If you try to boot the hypervisor on an Intel VT-enabled machine with Execute Disable Bit disabled in the BIOS, the hypervisor does not boot. The issue is recorded in the System Event log as: "Hypervisor launch failed; at least one of the processors in the system does not appear to support the features required by the hypervisor. (leaf: 2147483649, required features: 537921536, features available: 536872960)."
  To avoid this issue, make sure that Execute Disable is enabled in the BIOS before you try to launch the hypervisor. To fix this issue, enable Execute Disable and then reboot the computer.
• A computer may stop responding after a crash dump occurs when the hypervisor fails. When this issue occurs, a crash dump file will be created and the computer will display a blue screen. To fix the issue, reboot the computer.
• If the hypervisor fails to launch before the second reboot, no events will be present in the Event log to indicate this failure. Events for the hypervisor will not appear until after the second reboot occurs.

• 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.

• 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.
• Use of smartcard credentials does not work by default on Virtual Machine Connection as a way to log on to a virtual machine session. If you log on to a physical computer, open Virtual Machine Connection and try to log on to a virtual machine, you will receive an error message that an authentication error has occurred. To avoid this issue, use a user name and password to log on to a virtual machine session. If you must use smart card credentials to log on, you can edit the registry to allow use of the credentials. Under HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Credssp\PolicyDefaults, edit AllowDefaultCredentials if the computer is not joined to a domain, or edit AllowDefaultCredentialsDomain if the computer is joined to a domain. After you save the change, you will be prompted for your credentials and you can enter either your user name and password or your smartcard PIN.

This document supports a preliminary release of a software product that may be changed substantially prior to final commercial release. This document is provided for informational purposes only and Microsoft makes no warranties, either express or implied, in this document. Information in this document, including URL and other Internet Web site references, is subject to change without notice. The entire risk of the use or the results from the use of this document remains with the user. Unless otherwise noted, the companies, organizations, products, domain names, e-mail addresses, logos, people, places, and events depicted in examples herein are fictitious. No association with any real company, organization, product, domain name, e-mail address, logo, person, place, or event is intended or should be inferred. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation.

Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property.

© 2007 Microsoft Corporation. All rights reserved.

Microsoft, Hyper-V, and Windows Server are trademarks of the Microsoft group of companies.

All other trademarks are property of their respective owners.

2.1