http://www.theregister.co.uk/2011/09/14/windows_server_2008_overview/

Don’t despair! You can use the following generic PID to correct the issue:

263DJ-2Y9YT-6X9G6-W28DB-697TF

Hopefully we can get a bug fix from Microsoft sometime soon!

Proper guidelines for allocating processor cores to virtual machines in Hyper-V have been something that there seems to be a lot of questions out there on. There is conflicting information and seemingly little documentation to point us in the right direction. For example purposes I will write this article from the perspective of having a 3 node Hyper-V cluster with System Center Virtual Machine Manager in place to manage it all.

Host Cores

Each host has a finite and predetermined number of CPU cores available to it. This number depends on what type of processor is installed in the host, how many processors are installed on the host, and if those processors support hyper threading. Each of the Hyper-V servers that I will use as an example throughout will have 64 cores – 4 Intel Xeon X7550 2GHz processors each with 8 cores that support hyper threading (4*8*2 = 64).

Guest Cores

Each guest virtual machine can be assigned up to 4 virtual processors. This number determines the number of processors presented to the guest operating system. The speed of the virtual processors presented to the guest is always going to be the same as the speed of the processors in the host machine. In our environment this would mean that each virtual processor presented to a guest would have a speed of 2 GHz.

Overprovisioning Paranoia

One of the most common concerns with assigning the maximum number of cores to each guest (one that I have shared up until now) was overprovisioning of virtual processors vs. physical cores. The reasoning was that if you had X physical cores, but assigned X+1 (2, 3, etc.) virtual processors to guest machines that you could end up with a situation whereby there were more requests for processing power than could be handled by the physical host – potentially starving other VMs and / or the host machine itself of processing power.

This reasoning has proven to be incorrect for the reasons I will outline below.

There is not (nor has there ever been) a 1:1 relationship between virtual processors and cores on the host operating system. Each virtual processor simply represents a *potential* thread to be processed by the host machine’s cores. When a request for a thread is presented by an application, service, etc. to a guest machine, that is passed via the hypervisor to the parent partition for processing. The parent partition views this thread no differently than any other thread that would be sent by an application and it fulfills it as appropriate resources are available.

Based upon what I have laid out so far, you could still potentially run into a situation where heavy guest loads jeopardize the processing capability of other guest machines located on the same host and possibly the host itself – but this is not so! The guest processing requests will get queued as they come in and executed in order, so one machine cannot saturate a single (or multiple) cores with a constant stream of requests. In addition to this each cluster node has a setting that is controlled via System Center Virtual Machine Manager that reserves a set amount of processor time for the host machine itself which gives it priority when it otherwise might have to queue up its requests to the cores. The default is set at 20% of processor time, which is perhaps even a little too high depending on who you talk to.

System Center Virtual Machine Manager Processor Type Settings

To throw another variable in the mix, System Center Virtual Machine Manager has a setting under each virtual machine for selecting the “type” of virtual processor you want to give the machine (1.2GHz Athlon, 2.4GHz Xeon, etc.) – this setting (for all intents and purposes) is absolutely meaningless. All it does is allows you to set what your expected “performance level” is for the VM. It uses that along with the information about the performance of the host and other information to determine placement ratings (those little stars you see when selecting which host to place the VM on).

Conclusions and Recommendations

Based upon this information, and taking into account recommendations from a highly experienced technical professional that I have the pleasure of working with on how they configure their virtual machines & Hyper-V hosts, my recommendations are as follows:

1. Assign each VM 4 virtual processors of the default type (Athlon 1.2GHz MP in the current version of SCVMM), allowing it to execute the maximum number of simultaneous threads.
2. Reduce the reserved percentage of CPU time for the host from 20% to 10%.
3. Relax.

I hope this information proves valuable to all those out there that were struggling with the same concepts as me!

Windows IT Pro: The SCOM Service Level Dashboard

Recently I was working on a client’s system which runs Windows Small Business Server 2008 which, as you probably know, uses the Windows Internal Database Engine for the versions of SharePoint and WSUS (among a few other things) that are bundled with it.

Because the Windows Internal Database Engine that ships with SBS doesn’t offer any management tools, I was kind of stuck when I needed to change the recovery on a runaway SharePoint Config database.

After doing a little bit of research I came across across an article over MySQLTips.com (http://www.mssqltips.com/tip.asp?tip=1577) that got me going in the right direction.

In order to interact with the Windows Internal Database Engine, you must first download and install the SQL Management Studio Express (http://www.microsoft.com/downloads/details.aspx?FamilyID=08e52ac2-1d62-45f6-9a4a-4b76a8564a2b&displaylang=en).

Once that is complete, you can access the Windows Internal Database by connecting to the following (in the “server” field at the connection screen):

\\.\pipe\MSSQL$MICROSOFT##SSEE\sql\query

Once connected however, you may find that when trying to get to the properties of a database you are greeted with an error that says that the operation failed because the database has no owner.

Instead of messing around with the security settings of the database you can simply use standard SQL Query language in order to make the modifications you need. In my situation I just used the following to change the database recovery method:

ALTER DATABASE [DB_Name] SET RECOVERY SIMPLE
GO

Hopefully Microsoft will include more robust DB management tools out of the box in future releases of SBS.

The following ports need to be opened to allow for successful installation and communication with the DPM 2007 agents.

TCP: 5718, 5719, 135, 88, 139, 389
UDP: 53, 88, 137, 138, 389

Recently I was attempting to use Data Protection Manager 2007 to create a protection group that included volumes directly attached to the DPM server. I was slightly dismayed to see that I couldn’t install the protection agent on the machine or select anything other than the DPM configuration database in the New Protection Group wizard.

The answer, in my case, was to enable local data protection on the DPM server by executing the following command in the Data Protection Manager Console:

1

Set-DPMGlobalProperty -DPMServerName ServerName.Domain.Local -AllowLocalDataProtection $true

If you (or your organization) is lucky enough to get ahold of the Windows 7 RTM, you may encounter an issue that has been popping up for a small number of people.

After booting from the DVD (or USB Drive) that contains the Windows 7 installation files, and clicking Install, you will be greeted by an error message that says:

A Required CD/DVD Driver is Missing

I pounded my head against the wall for a while on this one. In my case it turned out to be a corrupt ISO file that was causing the issue, but here are some ideas for you to try before you throw your computer out a window.

(1) Download the Windows 7 ISO Verifier tool (http://www.istartedsomething.com/20090706/windows-7-iso-verifier/). It will check your ISO file, compare it to known good hashes and tell you if the image is good. Do this first!

(2) Unplug all unnecessary devices from your PC and attempt to install again.

(3) If you have a mixture of SATA and PATA devices, try to remove and / or replace the PATA devices and try to install again.

(4) Transfer the Windows 7 setup to a thumb drive (http://www.intowindows.com/how-to-install-windows-7vista-from-usb-drive-detailed-100-working-guide/), disconnect the CD / DVD-ROM and try to boot setup from that.

If that doesn’t work then post in the comments section and I will try to help you out.

I don’t remember where / when I applied, but last night I received an invitation to join the Microsoft Office 2010 Technical Preview!

I will post additional information about the software as I use it and learn more about its capabilities.