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Archive for August, 2008

Working with Hyper-V

August 15, 2008 Leave a comment
  • System Notes: Dell PowerEdge 2950, Windows 2008 Server Standard x64

The organization I work for started looking into our options for virtualization. We ran test versions of the free VMware Server and Microsoft Virtual Server 2005, and were not impressed with the performance of either. We then priced out a full VMware ESX Server setup, and that started at a minimum of $3,000, just for the software and a single license. The decision was made to wait for Windows Server 2008 with Hyper-V, based on early performance tests provided by Windows IT Pro, and the price point (included with Windows Server 2008, which we had already licensed several copies of).

The hardware we ended up purchasing was a mid-range Dell PowerEdge 2950 Server, with two quad-core processors and 16 gigs of RAM. Based on what we worked up with Dell, this should support up to 7 simultaneous virtual guests, depending on the load requirements of each guest.

We now have two 24×7 production virtual guests in use on this setup, with one having almost no load, while the other is a terminal server supporting up to 15 simultaneous users (but which probably has about 10% utilization in reality, as it only provides remote user support, and is not used as an application server). We do have four other “test” virtual guests, which are rarely used and are mainly for patch testing. Below are some issues and problems I have come across when running with Hyper-V.

  1. Windows 2000 Server Standard virtual guests have problems with the WMI subsystem at boot time. The Windows 2000 Server will be unavailable for approximately 5 minutes after boot, until three of these error messages are generated in the System Log: “Event Type: Warning, Event Source: WMI, Event Category: None, Event ID: 54, Description: The description for Event ID ( 54 ) in Source ( WMI ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. The following information is part of the event: \Device\WMIServiceDevice.” After that, the system functions normally, with no further unavailability or error messages. Here is a link to a discussion of this problem from the Microsoft TechNet Forums. I tried two different installations of Windows 2000 Server Standard, one from an MSDN CD (with SP4 integrated), the other from a retail CD (with SP3 integrated). Both had the same issue. I believe the problem comes from the Integration Components for Hyper-V being installed, but I have not yet verified this. We only have one physical production Windows 2000 Server left, and my original use for this guest was for patch testing.
  2. Domain time synchronization does not function correctly after the initial time set at boot up. Based on what I was able to find online here and on the Microsoft TechNet Forums, I disabled the Windows Time service (W32Time), and made sure the Time synchronization option was checked under the Integration Services options for the virtual guest in question (this option is checked by default). There have been no further time issues with the virtual guest after doing this. It would be nice if there were time synchronization notifications in the Windows event logs, especially when running in this configuration. Regardless, the physical host server is part of our domain, and is correctly synching with our time server, and the virtual guest is correctly staying on time.
  3. Occasionally, on our Windows Server 2003 virtual guest that is running as our terminal server, this error message will be generated in the Application Log: “Event Type: Error, Event Source: Userenv, Event Category: None, Event ID: 1054, Description: Windows cannot obtain the domain controller name for your computer network. (An unexpected network error occurred.). Group Policy processing aborted.” I have found no solution to this, nor does there seem to be any impact on the server from this error message. No functionality is lost, and users working on the server are not impacted. The server can correctly see and access all three of our domain controllers, both by name and by IP. The error seems to occur at random, sometimes once an hour, sometimes once in 24 hours.
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