Windows Server blog by Kurt Roggen [BE]

The VMM server initiates a series of specific refresh jobs at specific intervals.  Here’s an overview of what happens when…

Host Refresher
Runs every 30 minutes on every host (with time lags) and updates host properties. It also updates disk/SAN and host network (NIC / virtual switch) information. It does not check any VM related properties or performance counters on hosts. It can be manually triggered on the UI or through PS cmdlet Refresh-VMHost.

VM Heavy Refresher
Runs every 30 minutes on every host and also runs whenever a VM is clicked on (or when you call Refresh-VM PS cmdlet). It updates all VM properties, resource pools, clustering information for this VM and snapshots, but it does not update VM performance counter info.  It can be manually triggered on the UI or through the PS cmdlet Refresh-VM.

VM Light Refresher
Runs every 2 minutes on every host that is currently in the VMM database.
This refresher does the following:

    - Checks the host state (to see if the agent is running or the agent is down) and virtualization software status
    - Syncs the state of a VM
    - Marks VMs as missing 
    - Imports new VMs created outside of VMM (when VMM detects a new VM created, it is imported into VMM and launch the heavy refresher for this new VMs)

Cluster Refresher
Runs every 30 minutes and refreshes all cluster properties (including bringing in newly added nodes or taking our removed nodes). It can be manually triggered on the UI or through PS cmdlet Refresh-VMHostCluster.

Library Refresher
Runs on user configurable schedule (By default: every 1 hour, increments by 1 hour intervals and can be turned off completely) and updates the library shares info and metadata about library objects. It can be manually triggered on the UI or through PS cmdlet Refresh-LibraryShare.

Performance Refresher
Runs every 9 minutes on a host or whenever there is any state changing operation on the VM (start/stop/save/etc.). It collects performance counter information of both the host and all the VM’s on a given host.  The performance data is used for intelligent placement and the star rating calculation.

VirtualCenter Refresher
Runs every 30 minutes and refreshes VC properties, ESX hosts and resource pools that are managed by this VC. It can be manually triggered on the UI or through PS cmdlet Refresh-VirtualizationManager.

User Role Refresher
Runs every 30 minutes and updates user role properties.

PRO Tip Refresher
Runs every 30 seconds. It looks for PRO specific alerts in Operations Manager and reconciles the PRO tips in our DB against the data that is brought back from OpsMgr.  This refresher cannot be manually triggered.

More information: VMM Blog All about refreshers

Related reading:

• System Center Virtual Machine Manager 2008 R2 Cmdlet Reference

Hyper-V provides virtual machines with a pool of Media Access Control (MAC) addresses when Hyper-V is installed. Hyper-V has an algorithm to avoid duplicate MAC addresses on a single host, but not across multiple hosts. A crucial element in this algorithm is the Hyper-V host IPv4                                                                                                                              address (last 2 octets).

This article describes how MAC address pools work in Hyper-V, how it is possible to accidentally deploy hosts with duplicate MAC address pools, how to modify the default MAC pool and how using SCVMM 2008 to manage your Hyper-V hosts can prevent duplicate MAC addresses. 

The table below shows how to identify VM created with Hyper-V or VMM based in the MAC Address identifier.

NOTE: Since Windows Server 2008 R2 Hyper-V, you can change this MAC address pool from the Hyper-V Manager console instead of going through registry keys (MinimumMacAddress/MaximumMacAddress).

Learn more on how Hyper-V uses a MAC pool per Hyper-V host  and how VMM uses a MAC address pool for all VMHosts (Hyper-V, Virtual Server, VMware ESX).
For more information: VirtualizationAdmin.com: Dealing with MAC addresses in Hyper-V and VMM

Active Directory Web Services (ADWS) is a (new) windows service that enables remote management of any local directory service instance using WS-* (Web Services) protocols and is only present on domain controllers running Windows Server 2008 R2.

In a non-Windows Server 2008 R2 domain controller environment, the Active Directory Management Gateway Service enables administrators to use the Active Directory module for PowerShell and/or the “Active Directory Administrative Center” (ADAC) snapin - built on-top of PS and only available and running on Windows Server 2008 R2 or Windows 7 - to access or manage directory service instances that are running on Windows Server 2008 or Windows Server 2003 operating systems in the list below.

The Active Directory Management Gateway Service provides a web service interface to Active Directory domains and instances of Active Directory Lightweight Directory Services (AD LDS) or Active Directory Application Mode (ADAM) that are running on the same server as the Active Directory Management Gateway Service.

You can download and install the Active Directory Management Gateway Service on servers and domain controllers running the following operating systems:

1. Windows Server 2003 R2 with Service Pack 2 (SP2)
2. Windows Server 2003 SP2
3. Windows Server 2008
4. Windows Server 2008 SP2

The ADGMS provides the same ADWS functionality in a non-Windows Server 2008 R2 domain controller environment, hence its name “Management Gateway” service.

Here’s how the architecture looks like.

ADWS manages all directory service instances running on the server, including Domain Controller, Global Catalog and ADLDS instances.
The AD Web Service is implemented using WCF (Windows Communication Foundations) and listens on the registered TCP port 9389.

So in this way, you could start using the PowerShell modules for Active Directory from your Windows 7 workstation to automate some directory operations.

To get a list of available PS modules, use the cmdlet Get-Module.

PS:\> Get-Module –ListAvailable

To use a module, use the cmdlet Import-Module

PS:\> Import-Module ActiveDirectory

To get the cmdlets imported from a module, use the Get-Command cmdlet with the –Module parameter

PS:\> Get-Command –Module ActiveDirectory

To get a better understanding about the Active Directory PowerShell model, have a look below:

NOTE: You can install the Active Directory Management Gateway Service on writable domain controllers as well as read-only domain controllers that are running Windows Server 2008 or Windows Server 2008 SP2.
After it is installed on any of these operating systems, the Active Directory Management Gateway Service runs as the Windows Server 2008 R2 Active Directory Web Services (ADWS) service and provides the same functionality.

For more information about ADWS, see What's New in AD DS: Active Directory Web Services

NOTE: Installing the Active Directory Management Gateway Service on your Windows Server 2008–based or Windows Server 2003–based servers does not make it possible for you to install the Active Directory module or the Active Directory Administrative Center (which is available only on Windows Server 2008 R2 or Windows 7 operating systems) on these servers.

If the Active Directory Management Gateway Service on your Windows Server 2008 or Windows Server 2003 server is stopped or disabled, client applications, such as the Active Directory module or the Active Directory Administrative Center will not be able to access or manage any directory service instances that are running on this server.

Download ADMGS here

For more information:

• Active Directory PowerShell Blog: Active Directory Web Services Overview
• TechNet - What's New in AD DS: Active Directory Web Services
• Technet - What's New in AD DS: Active Directory Administrative Center

This 211-pages document describes the new and changed functionality and features available in Windows Server 2008 R2. The Windows Server 2008 R2 operating system includes changes to Windows Server 2008 features and technologies that help improve the security of computers running Windows Server 2008 R2, increase productivity, and reduce administrative overhead.

Download here

Related reading:

• Microsoft book: Introducing Windows Server 2008 R2 (MS Press)
• Microsoft white paper: Changes in Functionality from Windows Server 2003 SP1 to Windows Server 2008