Windows Sever 2008/R2 Interview questions Part 1
June 22, 2011 10 Comments
Difference between 2003 and 2008
1) 2008 is combination of vista and windows 2003r2. Some new services are introduced in it
1. RODC one new domain controller introduced in it [Read-only Domain controllers.]
2. WDS (windows deployment services) instead of RIS in 2003 server
3. shadow copy for each and every folders
4.boot sequence is changed
5.installation is 32 bit where as 2003 it is 16 as well as 32 bit, that’s why installation of 2008 is faster
6.services are known as role in it
7. Group policy editor is a separate option in ads
2) The main difference between 2003 and 2008 is Virtualization, management.
2008 has more inbuilt components and updated third party drivers Microsoft introduces new feature with 2k8 that is Hyper-V Windows Server 2008 introduces Hyper-V (V for Virtualization) but only on 64bit versions. More and more companies are seeing this as a way of reducing hardware costs by running several ‘virtual’ servers on one physical machine. If you like this exciting technology, make sure that you buy an edition of Windows Server 2008 that includes Hyper-V, then launch the Server Manger, add Roles.
Windows server 2008 new features
1. Virtualization with Hyper V
2. Server Core – provides the minimum installation required to carry out a specific server role, such as for a DHCP, DNS or print server. From a security standpoint, this is attractive. Fewer applications and services on the sever make for a smaller attack surface. In theory, there should also be less maintenance and management with fewer patches to install, and the whole server could take up as little as 3Gb of disk space according to Microsoft
3. IIS 7
4. Role based installation – rather than configuring a full server install for a particular role by uninstalling unnecessary components (and installing needed extras), you simply specify the role the server is to play, and Windows will install what’s necessary — nothing more.
5. Read Only Domain Controllers (RODC)
It’s hardly news that branch offices often lack skilled IT staff to administer their servers, but they also face another, less talked about problem. While corporate data centers are often physically secured, servers at branch offices rarely have the same physical security protecting them. This makes them a convenient launch pad for attacks back to the main corporate servers. RODC provides a way to make an Active Directory database read-only. Thus, any mischief carried out at the branch office cannot propagate its way back to poison the Active Directory system as a whole. It also reduces traffic on WAN links.
6. Enhanced terminal services
Terminal services has been beefed up in Server 2008 in a number of ways. TS RemoteApp enables remote users to access a centralized application (rather than an entire desktop) that appears to be running on the local computer’s hard drive. These apps can be accessed via a Web portal or directly by double-clicking on a correctly configured icon on the local machine. TS Gateway secures sessions, which are then tunnelled over https, so users don’t need to use a VPN to use RemoteApps securely over the Internet. Local printing has also been made significantly easier.
7. Network Access Protection
Microsoft’s system for ensuring that clients connecting to Server 2008 are patched, running a firewall and in compliance with corporate security policies — and that those that are not can be remediated — is useful. However, similar functionality has been and remains available from third parties.
8. Windows PowerShell
Restartable Active Directory Domain Services: You can now perform many actions, such as offline defragmentation of the database, simply by stopping Active Directory. This reduces the number of instances in which you must restart the server in Directory Services Restore Mode and thereby reduces the length of time the domain controller is unavailable to serve requests from
Enhancements to Group Policy: Microsoft has added many new policy settings. In particular, these settings enhance the management of Windows Vista client computers. All policy management is now handled by means of the Group Policy Management Console (GPMC), which was an optional feature first added to Windows Server 2003 R2. In addition, Microsoft has added new auditing capabilities to Group Policy and added a searchable database for locating policy settings from within GPMC. In Windows Server 2008 R2, GPMC enables you to use a series of PowerShell cmdlets to automate many of the tasks (such as maintenance and linking of GPOs) that you would otherwise perform in the GUI. In addition, R2 adds new policy settings that enhance the management of Windows 7 computers.
Windows Server 2008 R2 new features:
Active Directory Recycle Bin
Windows PowerShell 2.0
Active Directory Administrative Center (ADAC)
Offline domain join
Active Directory health check
Active Directory Web Services
Active Directory Management Pack
Windows Server Migration Tools
Managed Service Accounts
What is server core? How do you configure and manage a windows server 2008 core installation?
The Server Core installation option is an option that you can use for installing Windows Server 2008 or Windows Server 2008 R2. A Server Core installation provides a minimal environment for running specific server roles, which reduces the maintenance and management requirements and the attack surface for those server roles. A server running a Server Core installation of Windows Server 2008 supports the following server roles:
- Active Directory Domain Services (AD DS)
- Active Directory Lightweight Directory Services (AD LDS)
- DHCP Server
- DNS Server
- File Services
- Print Services
- Streaming Media Services
- Web Server (IIS)
A server running a Server Core installation of Windows Server 2008 R2 supports the following server roles:
- Active Directory Certificate Services
- Active Directory Domain Services
- Active Directory Lightweight Directory Services (AD LDS)
- DHCP Server
- DNS Server
- File Services (including File Server Resource Manager)
- Print and Document Services
- Streaming Media Services
- Web Server (including a subset of ASP.NET)
A Server Core installation does not include the traditional full graphical user interface. Once you have configured the server, you can manage it locally at a command prompt or remotely using a Terminal Server connection. You can also manage the server remotely using the Microsoft Management Console (MMC) or command-line tools that support remote use.
Benefits of a Server Core installation
The Server Core installation option of Windows Server 2008 or Windows Server 2008 R2 provides the following benefits:
- Reduced maintenance. Because the Server Core installation option installs only what is required to have a manageable server for the supported roles, less maintenance is required than on a full installation of Windows Server 2008.
- Reduced attack surface. Because Server Core installations are minimal, there are fewer applications running on the server, which decreases the attack surface.
- Reduced management. Because fewer applications and services are installed on a server running the Server Core installation, there is less to manage.
- Less disk space required. A Server Core installation requires only about 3.5 gigabytes (GB) of disk space to install and approximately 3 GB for operations after the installation.
How do you promote a Server Core to DC?
In order to install Active Directory DS on your server core machine you will need to perform the following tasks:
1. Configure an unattend text file, containing the instructions for the DCPROMO process. In this example you will create an additional DC for a domain called petrilab.local:
2. Configure the right server core settings
After that you need to make sure the core machine is properly configured.
- Perform any configuration setting that you require (tasks such as changing computer name, changing and configure IP address, subnet mask, default gateway, DNS address, firewall settings, configuring remote desktop and so on).
- After changing the required server configuration, make sure that for the task of creating it as a DC – you have the following requirements in place:
- A partition formatted with NTFS (you should, it’s a server…)
- A network interface card, configure properly with the right driver
- A network cable plugged in
- The right IP address, subnet mask, default gateway
And most importantly, do not forget:
- The right DNS setting, in most cases, pointing to an existing internal DNS in your corporate network
3. Copy the unattend file to the server core machine
Now you need to copy the unattend file from wherever you’ve stored it. You can run it from a network location but I prefer to have it locally on the core machine. You can use the NET USE command on server core to map to a network path and copy the file to the local drive. You can also use a regular server/workstation to graphically access the core’s C$ drive (for example) and copy the file to that location.
4. Run the DCPROMO process
Next you need to manually run DCPROMO. To run the Active Directory Domain Services Installation Wizard in unattended mode, use the following command at a command prompt:
Reboot the machine
In order to reboot the server core machine type the following text in the command prompt and press Enter.
shutdown /r /t 0
What are RODCs? What are advantages?
A read-only domain controller (RODC) is a new type of domain controller in the Windows Server® 2008 operating system. With an RODC, organizations can easily deploy a domain controller in locations where physical security cannot be guaranteed. An RODC hosts read-only partitions of the Active Directory Domain Services (AD DS) database.
Before the release of Windows Server 2008, if users had to authenticate with a domain controller over a wide area network (WAN), there was no real alternative. In many cases, this was not an efficient solution. Branch offices often cannot provide the adequate physical security that is required for a writable domain controller. Furthermore, branch offices often have poor network bandwidth when they are connected to a hub site. This can increase the amount of time that is required to log on. It can also hamper access to network resources.
Beginning with Windows Server 2008, an organization can deploy an RODC to address these problems. As a result, users in this situation can receive the following benefits:
- Improved security
- Faster logon times
- More efficient access to resources on the network
What does an RODC do?
Inadequate physical security is the most common reason to consider deploying an RODC. An RODC provides a way to deploy a domain controller more securely in locations that require fast and reliable authentication services but cannot ensure physical security for a writable domain controller.
However, your organization may also choose to deploy an RODC for special administrative requirements. For example, a line-of-business (LOB) application may run successfully only if it is installed on a domain controller. Or, the domain controller might be the only server in the branch office, and it may have to host server applications.
In such cases, the LOB application owner must often log on to the domain controller interactively or use Terminal Services to configure and manage the application. This situation creates a security risk that may be unacceptable on a writable domain controller.
An RODC provides a more secure mechanism for deploying a domain controller in this scenario. You can grant a non administrative domain user the right to log on to an RODC while minimizing the security risk to the Active Directory forest.
You might also deploy an RODC in other scenarios where local storage of all domain user passwords is a primary threat, for example, in an extranet or application-facing role.
How do you install an RODC?
1 Make sure you are a member of Domain Admin group
2. Ensure that the forest functional level is Windows Server 2003 or higher
3. Run adprep /rodcprep
3. Install a writable domain controller that runs Windows Server 2008 – An RODC must replicate domain updates from a writable domain controller that runs Windows Server 2008. Before you install an RODC, be sure to install a writable domain controller that runs Windows Server 2008 in the same domain. The domain controller can run either a full installation or a Server Core installation of Windows Server 2008. In Windows Server 2008, the writable domain controller does not have to hold the primary domain controller (PDC) emulator operations master role.
4. You can install an RODC on either a full installation of Windows Server 2008 or on a Server Core installation of Windows Server 2008. Follow the below steps:
- Click Start, type dcpromo, and then press ENTER to start the Active Directory Domain Services Installation Wizard.
- On the Choose a Deployment Configuration page, click Existing forest, click Add a domain controller to an existing domain
- On the Network Credentials page, type the name of a domain in the forest where you plan to install the RODC. If necessary, also type a user name and password for a member of the Domain Admins group, and then click Next.
- Select the domain for the RODC, and then click Next.
- Click the Active Directory site for the RODC and click next
- Select the Read-only domain controller check box, as shown in the following illustration. By default, the DNS server check box is also selected. To run the DNS server on the RODC, another domain controller running Windows Server 2008 must be running in the domain and hosting the DNS domain zone. An Active Directory–integrated zone on an RODC is always a read-only copy of the zone file. Updates are sent to a DNS server in a hub site instead of being made locally on the RODC.
- To use the default folders that are specified for the Active Directory database, the log files, and SYSVOL, click Next.
- Type and then confirm a Directory Services Restore Mode password, and then click Next.
- Confirm the information that appears on the Summary page, and then click Next to start the AD DS installation. You can select the Reboot on completion check box to make the rest of the installation complete automatically.
What is the minimum requirement to install Windows 2008 server?
Talk about all the AD-related roles in Windows Server 2008/R2.
Active Directory Domain Services
Active Directory Domain Services (AD DS), formerly known as Active Directory Directory Services, is the central location for configuration information, authentication requests, and information about all of the objects that are stored within your forest. Using Active Directory, you can efficiently manage users, computers, groups, printers, applications, and other directory-enabled objects from one secure, centralized location.
- Lower costs of managing Windows networks.
- Simplify identity management by providing a single view of all user information.
- Boost security with the ability to enable multiple types of security mechanisms within a single network.
- Improve compliance by using Active Directory as a primary source for audit data.
Active Directory Rights Management Services
Your organization’s intellectual property needs to be safe and highly secure. Active Directory Rights Management Services, a component of Windows Server 2008, is available to help make sure that only those individuals who need to view a file can do so. AD RMS can protect a file by identifying the rights that a user has to the file. Rights can be configured to allow a user to open, modify, print, forward, or take other actions with the rights-managed information. With AD RMS, you can now safeguard data when it is distributed outside of your network.
Active Directory Federation Services
Active Directory Federation Services is a highly secure, highly extensible, and Internet-scalable identity access solution that allows organizations to authenticate users from partner organizations. Using AD FS in Windows Server 2008, you can simply and very securely grant external users access to your organization’s domain resources. AD FS can also simplify integration between untrusted resources and domain resources within your own organization.
Active Directory Certificate Services
Most organizations use certificates to prove the identity of users or computers, as well as to encrypt data during transmission across unsecured network connections. Active Directory Certificate Services (AD CS) enhances security by binding the identity of a person, device, or service to their own private key. Storing the certificate and private key within Active Directory helps securely protect the identity, and Active Directory becomes the centralized location for retrieving the appropriate information when an application places a request.
Active Directory Lightweight Directory Services
Active Directory Lightweight Directory Service (AD LDS), formerly known as Active Directory Application Mode, can be used to provide directory services for directory-enabled applications. Instead of using your organization’s AD DS database to store the directory-enabled application data, AD LDS can be used to store the data. AD LDS can be used in conjunction with AD DS so that you can have a central location for security accounts (AD DS) and another location to support the application configuration and directory data (AD LDS). Using AD LDS, you can reduce the overhead associated with Active Directory replication, you do not have to extend the Active Directory schema to support the application, and you can partition the directory structure so that the AD LDS service is only deployed to the servers that need to support the directory-enabled application.
What are the new Domain and Forest Functional Levels in Windows Server 2008/R2?
Domain Function Levels
To activate a new domain function level, all DCs in the domain must be running the right operating system. After this requirement is met, the administrator can raise the domain functional level. Here’s a list of the available domain function levels available in Windows Server 2008:
Windows 2000 Native Mode
This is the default function level for new Windows Server 2008 Active Directory domains.
Supported Domain controllers – Windows 2000, Windows Server 2003, Windows Server 2008.
Windows Server 2003 Mode
To activate the new domain features, all domain controllers in the domain must be running Windows Server 2003. After this requirement is met, the administrator can raise the domain functional level to Windows Server 2003.
Supported Domain controllers – Windows Server 2003, Windows Server 2008.
Windows Server 2008 Mode
Supported Domain controllers – Windows Server 2008.
Windows 2008 Forest function levels
Forest functionality activates features across all the domains in your forest. To activate a new forest function level, all the domain in the forest must be running the right operating system and be set to the right domain function level. After this requirement is met, the administrator can raise the forest functional level. Here’s a list of the available forest function levels available in Windows Server 2008:
Windows 2000 forest function level
This is the default setting for new Windows Server 2008 Active Directory forests.
Supported Domain controllers in all domains in the forest – Windows 2000, Windows Server 2003, Windows Server 2008.
Windows Server 2003 forest function level
To activate new forest-wide features, all domain controllers in the forest must be running Windows Server 2003.
Supported Domain controllers in all domains in the forest – Windows Server 2003, Windows Server 2008.
Windows Server 2008 forest function level
To activate new forest-wide features, all domain controllers in the forest must be running Windows Server 2008.
Supported Domain controllers in all domains in the forest – Windows Server 2008.
To activate the new domain features, all domain controllers in the domain must be running Windows Server 2008. After this requirement is met, the administrator can raise the domain functional level to Windows Server 2008.
When a child domain is created in the domain tree, what type of trust relationship exists between the new child domain and the trees root domain?
Transitive and two way.
Which Windows Server 2008 tools make it easy to manage and configure a servers roles and features?
The Server Manager window enables you to view the roles and features installed on a server and also to quickly access the tools used to manage these various roles and features. The Server Manager can be used to add and remove roles and features as needed
What is WDS? How is WDS configured and managed on a server running Windows Server 2008?
The Windows Deployment Services is the updated and redesigned version of Remote Installation Services (RIS). Windows Deployment Services enables you to deploy Windows operating systems, particularly Windows Vista. You can use it to set up new computers by using a network-based installation. This means that you do not have to install each operating system directly from a CD or DVD.
Benefits of Windows Deployment Services
Windows Deployment Services provides organizations with the following benefits:
- Allows network-based installation of Windows operating systems, which reduces the complexity and cost when compared to manual installations.
- Deploys Windows images to computers without operating systems.
- Supports mixed environments that include Windows Vista, Microsoft Windows XP and Microsoft Windows Server 2003.
- Built on standard Windows Vista setup technologies including Windows PE, .wim files, and image-based setup.
Prerequisites for installing Windows Deployment Services
Your computing environment must meet the following technical requirements to install Windows Deployment Services:
- Active Directory. A Windows Deployment Services server must be either a member of an Active Directory domain or a domain controller for an Active Directory domain. The Active Directory domain and forest versions are irrelevant; all domain and forest configurations support Windows Deployment Services.
- DHCP. You must have a working Dynamic Host Configuration Protocol (DHCP) server with an active scope on the network because Windows Deployment Services uses PXE, which relies on DHCP for IP addressing.
- DNS. You must have a working Dynamic Name Services (DNS) server on the network to run Windows Deployment Services.
- An NTFS partition. The server running Windows Deployment Services requires an NTFS file system volume for the image store.
- Credentials. To install the role, you must be a member of the Local Administrators group on the Windows Deployment Services server. To install an image, you must be a member of the Domain Users group.
- Windows Server 2003 SP1 or SP2 with RIS installed. RIS does not have to be configured, but must be installed.
Name some of the major changes in GPO in Windows Server 2008.
Cost savings through power options
In Windows Server 2008, all power options have been Group Policy enabled, providing a potentially significant cost savings. Controlling power options through Group Policy could save organizations a significant amount of money. You can modify specific power options through individual Group Policy settings or build a custom power plan that is deployable by using Group Policy.
Ability to block device installation
In Windows Server 2008, you can centrally restrict devices from being installed on computers in your organization. You will now be able to create policy settings to control access to devices such as USB drives, CD-RW drives, DVD-RW drives, and other removable media.
Improved security settings
In Windows Server 2008, the firewall and IPsec Group Policy settings are combined to allow you to leverage the advantages of both technologies, while eliminating the need to create and maintain duplicate functionality. Some scenarios supported by these combined firewall and IPsec policy settings are secure server-to-server communications over the Internet, limiting access to domain resources based on trust relationships or health of a computer, and protecting data communication to a specific server to meet regulatory requirements for data privacy and security.
Expanded Internet Explorer settings management
In Windows Server 2008, you can open and edit Internet Explorer Group Policy settings without the risk of inadvertently altering the state of the policy setting based on the configuration of the administrative workstation. This change replaces earlier behavior in which some Internet Explorer policy settings would change based on the policy settings enabled on the administrative workstation used to view the settings
Printer assignment based on location
The ability to assign printers based on location in the organization or a geographic location is a new feature in Windows Server 2008. In Windows Server 2008, you can assign printers based on site location. When mobile users move to a different location, Group Policy can update their printers for the new location. Mobile users returning to their primary locations see their usual default printers.
Printer driver installation delegated to users
In Windows Server 2008, administrators can now delegate to users the ability to install printer drivers by using Group Policy. This feature helps to maintain security by limiting distribution of administrative credentials.
What is the AD Recycle Bin? How do you use it?
Active Directory Recycle Bin helps minimize directory service downtime by enhancing your ability to preserve and restore accidentally deleted Active Directory objects without restoring Active Directory data from backups, restarting Active Directory Domain Services (AD DS), or rebooting domain controllers.
When you enable Active Directory Recycle Bin, all link-valued and non-link-valued attributes of the deleted Active Directory objects are preserved and the objects are restored in their entirety to the same consistent logical state that they were in immediately before deletion. For example, restored user accounts automatically regain all group memberships and corresponding access rights that they had immediately before deletion, within and across domains.
Active Directory Recycle Bin is functional for both AD DS and Active Directory Lightweight Directory Services (AD LDS) environments.
By default, Active Directory Recycle Bin in Windows Server 2008 R2 is disabled. To enable it, you must first raise the forest functional level of your AD DS or AD LDS environment to Windows Server 2008 R2, which in turn requires all forest domain controllers or all servers that host instances of AD LDS configuration sets to be running Windows Server 2008 R2.
To enable Active Directory Recycle Bin using the Enable-ADOptionalFeature cmdlet
1. Click Start, click Administrative Tools, right-click Active Directory Module for Windows PowerShell, and then click Run as administrator.
- At the Active Directory module for Windows PowerShell command prompt, type the following command, and then press ENTER:
Enable-ADOptionalFeature -Identity <ADOptionalFeature> -Scope <ADOptionalFeatureScope> -Target <ADEntity>
For example, to enable Active Directory Recycle Bin for contoso.com, type the following command, and then press ENTER:
Enable-ADOptionalFeature –Identity ‘CN=Recycle Bin Feature,CN=Optional Features,CN=Directory Service,CN=Windows NT,CN=Services,CN=Configuration,DC=contoso,DC=com’ –Scope ForestOrConfigurationSet –Target ‘contoso.com’
What are AD Snapshots? How do you use them?
A snapshot is a shadow copy—created by the Volume Shadow Copy Service (VSS)—of the volumes that contain the Active Directory database and log files. With Active Directory snapshots, you can view the data inside such a snapshot on a domain controller without the need to start the server in Directory Services Restore Mode.
Windows Server 2008 has a new feature allowing administrators to create snapshots of the Active Directory database for offline use. With AD snapshots you can mount a backup of AD DS under a different set of ports and have read-only access to your backups through LDAP.
There are quite a few scenarios for using AD snapshots. For example, if someone has changed properties of AD objects and you need to revert to their previous values, you can mount a copy of a previous snapshot to an alternate port and easily export the required attributes for every object that was changed. These values can then be imported into the running instance of AD DS. You can also restore deleted objects or simply view objects for diagnostic purposes.
It does not allow you to move or copy items or information from the snapshot to the live database. In order to do that you will need to manually export the relevant objects or attributes from the snapshot, and manually import them back to the live AD database.
Steps for using Snapshot:1. Create a snapshot:
open CMD.exe, Ntdsutil, activate instance ntds, snapshot, create, list all.
2. Mounting an Active Directory snapshot:
Before connecting to the snapshot we need to mount it. By looking at the results of the List All command in above step, identify the snapshot that you wish to mount, and note the number next to it.
Type Ntdsutil, Snapshot, List all, Mount 2. The snapshot gets mounted to c:\$SNAP_200901250030_VOLUMEC$. Now you can refer this path to see the objects in these snapshots.
3. Connecting an Active Directory snapshot:
In order to connect to the AD snapshot you’ve mounted you will need to use the DSAMAIN command. DSAMAIN is a command-line tool that is built into Windows Server 2008. It is available if you have the Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS) server role installed.
After using DSAMAIN to expose the information inside the AD snapshot, you can use any GUI tool that can connect to the specified port, tools such as Active Directory Users and Computers (DSA.msc), ADSIEDIT.msc, LDP.exe or others. You can also connect to it by using command line tools such as LDIFDE or CSVDE, tools that allow you to export information from that database.
dsamain -dbpath ” c:\$SNAP_200901250030_VOLUMEC$\Windows\NTDS\ntds.dit” -ldapport 10289
The above command will allow you to access the database using port 10289.
Now you can use LDP.exe tool to connect to this mounted instance.
4. Disconnecting from the Active Directory snapshot:
In order to disconnect from the AD snapshot all you need to do is to type CTRL+C at the DSAMAIN command prompt window. You’ll get a message indicating that the DS shut down successfully.
5. Unmounting the snapshot:
Run command, Ntdsutil, Snapshot, List all, Unmount 2.
What is Offline Domain Join? How do you use it?
You can use offline domain join to join computers to a domain without contacting a domain controller over the network. You can join computers to the domain when they first start up after an operating system installation. No additional restart is necessary to complete the domain join. This helps reduce the time and effort required to complete a large-scale computer deployment in places such as datacenters.
For example, an organization might need to deploy many virtual machines within a datacenter. Offine domain join makes it possible for the virtual machines to be joined to the domain when they initially start following the operating system installation. No additional restart is required to complete the domain join. This can significantly reduce the overall time required for wide-scale virtual machine deployments.
A domain join establishes a trust relationship between a computer running a Windows operating system and an Active Directory domain. This operation requires state changes to AD DS and state changes on the computer that is joining the domain. To complete a domain join in the past using previous Windows operating systems, the computer that joined the domain had to be running and it had to have network connectivity to contact a domain controller. Offline domain join provides the following advantages over the previous requirements:
- The Active Directory state changes are completed without any network traffic to the computer.
- The computer state changes are completed without any network traffic to a domain controller.
- Each set of changes can be completed at a different time.
What are Fine-Grained Passwords? How do you use them?
You can use fine-grained password policies to specify multiple password policies within a single domain. You can use fine-grained password policies to apply different restrictions for password and account lockout policies to different sets of users in a domain.
For example, you can apply stricter settings to privileged accounts and less strict settings to the accounts of other users. In other cases, you might want to apply a special password policy for accounts whose passwords are synchronized with other data sources.
Talk about Restartable Active Directory Domain Services in Windows Server 2008/R2. What is this feature good for?
Restartable AD DS is a feature in Windows Server 2008 that you can use to perform routine maintenance tasks on a domain controller, such as applying updates or performing offline defragmentation, without restarting the server.
While AD DS is running, a domain controller running Windows Server 2008 behaves the same way as a domain controller running Microsoft® Windows® 2000 Server or Windows Server 2003.
While AD DS is stopped, you can continue to log on to the domain by using a domain account if other domain controllers are available to service the logon request. You can also log on to the domain with a domain account while the domain controller is started in Directory Services Restore Mode (DSRM) if other domain controllers are available to service the logon request.
If no other domain controller is available, you can log on to the domain controller where AD DS is stopped in Directory Services Restore Mode (DSRM) only by using the DSRM Administrator account and password by default, as in Windows 2000 Server Active Directory or Windows Server 2003 Active Directory.
Benefits of restartable AD DS
Restartable AD DS reduces the time that is required to perform offline operations such as offline defragmentation. It also improves the availability of other services that run on a domain controller by keeping them running when AD DS is stopped. In combination with the Server Core installation option of Windows Server 2008, restartable AD DS reduces the overall servicing requirements of a domain controller.
In Windows 2000 Server Active Directory and Windows Server 2003 Active Directory, you must restart the domain controller in DSRM when you perform offline defragmentation of the database or apply security updates. In contrast, you can stop Windows Server 2008 AD DS as you stop other services that are running locally on the server. This makes it possible to perform offline AD DS operations more quickly than you could with Windows 2000 Server and Windows Server 2003.
You can use Microsoft Management Console (MMC) snap-ins, or the Net.exe command-line tool, to stop or restart Active Directory® Domain Services (AD DS) in the Windows Server® 2008 operating system. You can stop AD DS to perform tasks, such as offline defragmentation of the AD DS database, without restarting the domain controller. Other services that run on the server, but that do not depend on AD DS to function, are available to service client requests while AD DS is stopped. An example of such a service is Dynamic Host Configuration Protocol (DHCP).