HI all,
These are some interview questions that will help you.I am not the author for all the questions.I found these questions from different blogs and websites.So thank you so much to their respective authors.
What is Global Catalog and its function?
The global catalog is a distributed data repository that contains a searchable, partial representation of every object in every domain in a multidomain Active Directory Domain Services (AD DS) forest. The global catalog is stored on domain controllers that have been designated as global catalog servers and is distributed through multimaster replication. Searches that are directed to the global catalog are faster because they do not involve referrals to different domain controllers.
The global catalog provides the ability to locate objects from any domain without having to know the domain name. A global catalog server is a domain controller that, in addition to its full, writable domain directory partition replica, also stores a partial, read-only replica of all other domain directory partitions in the forest.
- Forest-wide searches. The global catalog provides a resource for searching an AD DS forest. Forest-wide searches are identified by the LDAP port that they use. If the search query uses port 3268, the query is sent to a global catalog server.
- User logon. In a forest that has more than one domain, two
conditions require the global catalog during user authentication:
Universal Group Membership Caching: In a forest that has more than one
domain, in sites that have domain users but no global catalog server,
Universal Group Membership Caching can be used to enable caching of
logon credentials so that the global catalog does not have to be
contacted for subsequent user logons. This feature eliminates the need
to retrieve universal group memberships across a WAN link from a global
catalog server in a different site.
- In a domain that operates at the Windows 2000 native domain functional level or higher, domain controllers must request universal group membership enumeration from a global catalog server.
- When a user principal name (UPN) is used at logon and the forest has more than one domain, a global catalog server is required to resolve the name.
- Exchange Address Book lookups. Servers running Microsoft Exchange Server rely on access to the global catalog for address information. Users use global catalog servers to access the global address list (GAL).
What are the components of Logical AD?
The logical parts of Active Directory include forests, trees, domains, OUs and global catalogs.
Domain –It is still a logical group of users and computers that share the characteristics of centralized security and administration. A domain is still a boundary for security – this means that an administrator of a domain is an administrator for only that domain, and no others, by default.
Tree – a tree is a collection of Active Directory domains that share a contiguous namespace.
Forest – a forest is the largest unit in Active Directory and is a collection of trees that share a common Schema. In a forest all trees are connected by transitive two-way trust relationships, thus allowing users in any tree access to resources in another for which they have been given appropriate permissions and rights. By default the first domain created in a forest is referred to as the root domain.
What are the different Partition in AD and explain all?
The Active Directory database is logically separated into directory partitions:
- Schema partition
- Configuration partition
- Domain partition
- Application partition
Schema Partition
Only one schema partition exists per forest. The schema partition is stored on all domain controllers in a forest. The schema partition contains definitions of all objects and attributes that you can create in the directory, and the rules for creating and manipulating them. Schema information is replicated to all domain controllers in the attribute definitions.
Configuration Partition
There is only one configuration partition per forest. Second on all domain controllers in a forest, the configuration partition contains information about the forest-wide active directory structure including what domains and sites exist, which domain controllers exist in each forest, and which services are available. Configuration information is replicated to all domain controllers in a forest.
Domain Partition
Many domain partitions can exist per forest. Domain partitions are stored on each domain controller in a given domain. A domain partition contains information about users, groups, computers and organizational units. The domain partition is replicated to all domain controllers of that domain. All objects in every domain partition in a forest are stored in the global catalog with only a subset of their attribute values.
Application Partition
Application partitions store information about application in Active Directory. Each application determines how it stores, categorizes, and uses application specific information. To prevent unnecessary replication to specific application partitions, you can designate which domain controllers in a forest host specific application partitions. Unlike a domain partitions, an application partition cannot store security principal objects, such as user accounts. In addition, the data in an application partition is not stored in the global catalog.
As an example of application partition, if you use a Domain Name System (DNS) that is integrated with Active Directory you have two application partitions for DNS zones — ForestDNSZones and DomainDNSZones:
- ForestDNSZones is part of a forest. All domain controllers and DNS servers in a forest receive a replica of this partition. A forest-wide application partition stores the forest zone data.
- DomainDNSZones is unique for each domain. All domain controllers that are DNS servers in that domain receive a replica of this partition. The application partitions store the domain DNS zone in the DomainDNSZones<domain name>.
Different types of Disk partition?
How many types of RAID and explain any 3 advantage and disadvantage?
http://yourcomputer.in/what-is-raid-configuration-in-windows/
RAID Levels and Types
RAID, an acronym of Redundant Array of Independent (Inexpensive) Disks is the talk of the day. These are an array of disk to give more power, performance, fault tolerance and accessibility to the data, as a single storage system. It’s not mere combination of disks but all the disks are combined providing standard MTBF (mean time before failure) reliability scheme; otherwise chances are performance would be affected drastically if disks are not combined as a single storage unit.
RAID Levels
| All the RAID types and models are commonly classified as RAID levels, since RAID represented by a higher number is regarded to be superior, more efficient, high-performance array than the low numbered RAID. Hence, high security feature of RAID also depends on the RAID level you are using. RAID arrays, not only, provide the users with maximum security and reliability but also make sure that if a disk fails no data is lost. The in-depth knowledge about RAID levels would help you through buying of RAID servers.Let’s briefly discuss here the main RAID levels and classes: |
It is the Stripped Disk Array with no fault tolerance and it requires at least 2 drives to be implemented. Due to no redundancy feature, RAID 0 is considered to be the lowest ranked RAID level. Striped data mapping technique is implemented for high performance at low cost. The I/O performance is also improved as it is loaded across many channels. Regeneration, Rebuilding and functional redundancy are some salient features of RAID 0.
RAID 1 – Mirroring:
It is the Mirroring (Shadowing) Array meant to provide high performance. RAID 1 controller is able to perform 2 separate parallel reads or writes per mirrored pair. It also requires at least 2 drives to implement a non-redundant disk array. High level of availability, access and reliability can be achieved by entry-level RAID 1 array. With full redundancy feature available, need of readability is almost negligible. Controller configurations and storage subsystem design is the easiest and simplest amongst all RAID levels.
RAID 0+1:
It is the RAID array providing high data transference performance with at least 4 disks needed to implement the RAID 0+1 level. It’s a unique combination of stripping and mirroring with all the best features of RAID 0 and RAID 1 included such as fast data access and fault tolerance at single drive level. The multiple stripe segments have added high I/O rates to the RAID performance and it is the best solution for maximum reliability.
RAID 2 (ECC):
It is the combination of Inherently Parallel Mapping and Protection RAID array. It’s also known as ECC RAID because each data word bit is written to data disk which is verified for correct data or correct disk error when the RAID disk is read. Due to special disk features required, RAID 2 is not very popular among the corporate data storage masses, despite the extremely high data transference rates.
RAID 3:
RAID 3 works on the Parallel Transfer with Parity technique. The least number of disks required to implement the RAID array is 3 disks. In the RAID 3, data blocks are striped and written on data drives and then the stripe parity is generated, saved and afterwards used to verify the disk reads. Read and write data transfer rate is very high in RAID 3 array and disk failure causes insignificant effects on the overall performance of the RAID.
RAID 4:
RAID 4 requires a minimum of 3 drives to be implemented. It is composed of independent disks with shared parity to protect the data. Data transaction rate for Read is exceptionally high and highly aggregated. Similarly, the low ratio of parity disks to data disks indicates high efficiency.
RAID 5:
RAIDS 5 is Independent Distributed parity block of data disks with a minimum requirement of at least 3 drives to be implemented and N-1 array capacity. It helps in reducing the write inherence found in RAID 4. RAID 5 array offers highest data transaction Read rate, medium data transaction Write rate and good cumulative transfer rate.
RAID 6:
RAIDS 6 is Independent Data Disk array with Independent Distributed parity. It is known to be an extension of RAID level 5 with extra fault tolerance and distributed parity scheme added. RAID 6 is the best available RAID array for mission critical applications and data storage needs, though the controller design is very complex and overheads are extremely high.
RAID 7:
RAID 7 is the Optimized Asynchrony array for high I/O and data transfer rates and is considered to be the most manageable RAID controller available. The overall write performance is also known to be 50% to 90% better and improved than the single spindle array levels with no extra data transference required for parity handling. RAID 7 is registered as a standard trademark of Storage Computer Corporation.
RAID 10:
RAID 10 is classified as the futuristic RAID controller with extremely high Reliability and performance embedded in a single RAID controller. The minimum requirement to form a RAID level 10 controller is 4 data disks. The implementation of RAID 10 is based on a striped array of RAID 1 array segments, with almost the same fault tolerance level as RAID 1. RAID 10 controllers and arrays are suitable for uncompromising availability and extremely high throughput required systems and environment.
With all the significant RAID levels discussed here briefly, another important point to add is that whichever level of RAID is used regular and consistent data backup maintenance using tape storage is must as the regular tape storage is best media to recover from lost data scene.
What is FSMO Roles?
Click here to know about FSMO in detail
How to find which server hold which role?
Netdom query FSMO
How we can replication monitoring?
The Active Directory Replication Monitor, replmon.exe, is part of the Windows 2000 Support Utilities available on the Windows 2000 Server CD in the \SUPPORT\TOOLS folder. Primary uses of replmon :
- Check for replication errors
- Run the KCC Knowledge Consistency Checker to check replication topology
- Synchronize each directory partition with all servers
- Generate status reports on replication info on servers
- List domain controllers
- Check Group Policy Object status
- Choose performance counters to be monitored
- List server hosting Global Catalog
- List bridgehead servers
- Display trust relationships List AD meta-data info
What is intersite and Intra site replication explain?
http://technet.microsoft.com/en-us/library/cc755994(WS.10).aspx
What is Authoritative and Non authorities restoration?
Active Directory is backed up as part of system state, a collection of system components that depend on each other. You must back up and restore system state components together.
Components that comprise the system state on a domain controller include:
- System Start-up Files (boot files). These are the files required for Windows 2000 Server to start.
- System registry.
- Class registration database of Component Services. The Component Object Model (COM) is a binary standard for writing component software in a distributed systems environment.
- SYSVOL. The system volume provides a default Active
Directory location for files that must be shared for common access
throughout a domain. The SYSVOL folder on a domain controller contains:
- NETLOGON shared folders. These usually host user logon scripts and Group Policy objects (GPOs) for non-Windows 2000based network clients.
- User logon scripts for Windows 2000 Professionalbased clients and clients that are running Windows 95, Windows 98, or Windows NT 4.0.
- Windows 2000 GPOs.
- File system junctions.
- File Replication service (FRS) staging directories and files that are required to be available and synchronized between domain controllers.
- Active Directory. Active Directory includes:
- Ntds.dit: The Active Directory database.
- Edb.chk: The checkpoint file.
- Edb*.log: The transaction logs, each 10 megabytes (MB) in size.
- Res1.log and Res2.log: Reserved transaction logs.
Non-authoritative restore of Active Directory
A non-authoritative restore returns the domain controller to its state at the time of backup, then allows normal replication to overwrite that state with any changes that have occurred after the backup was taken. After you restore the system state, the domain controller queries its replication partners. The replication partners replicate any changes to the restored domain controller, ensuring that the domain controller has an accurate and updated copy of the Active Directory database.
Non-authoritative restore is the default method for restoring Active Directory, and you will use it in most situations that result from Active Directory data loss or corruption. To perform a non-authoritative restore, you must be able to start the domain controller in Directory Services Restore Mode.
Non-authoritative restore of SYSVOL
When you non-authoritatively restore the SYSVOL, the local copy of SYSVOL on the restored domain controller is compared with that of its replication partners. After the domain controller restarts, it contacts its replication partners, compares SYSVOL information, and replicate the any necessary changes, bringing it up-to-date with the other domain controllers within the domain.
Perform a non-authoritative restore of SYSVOL if at least one other functioning domain controller exists in the domain. This is the default method for restoring SYSVOL and occurs automatically if you perform a non-authoritative restore of the Active Directory.
If no other functioning domain controller exists in the domain, then perform a primary restore of the SYSVOL. A primary restore builds a new File Replication service (FRS) database by loading the data present under SYSVOL on the local domain controller. This method is the same as a non-authoritative restore, except that the SYSVOL is marked primary.
Authoritative restore of Active Directory
An authoritative restore is an extension of the non-authoritative restore process. You must perform the steps of a non-authoritative restore before you can perform an authoritative restore. The main difference is that an authoritative restore has the ability to increment the version number of the attributes of all objects in an entire directory, all objects in a subtree, or an individual object (provided that it is a leaf object) to make it authoritative in the directory. Restore the smallest unit necessary, for example, do not restore the entire directory in order to restore a single subtree.
As with a non-authoritative restore, after a domain controller is back online, it will contact its replication partners to determine any changes since the time of the last backup. However, because the version number of the object attributes that you want to be authoritative will be higher than the existing version numbers of the attribute held on replication partners, the object on the restored domain controller will appear to be more recent and therefore will be replicated out to the rest of the domain controllers within the environment.
Unlike a non-authoritative restore, an authoritative restore requires the use of a separate tool, Ntdsutil.exe. No backup utilities— including the Windows 2000 Server system tools— can perform an authoritative restore.
An authoritative restore will not overwrite new objects that have been created after the backup was taken. You can authoritatively restore only objects from the configuration and domain-naming contexts. Authoritative restores of schema-naming contexts are not supported.
Perform an authoritative restore when human error is involved, such as when an administrator accidentally deletes a number of objects and that change replicates to the other domain controllers and you cannot easily recreate the objects. To perform an authoritative restore, you must start the domain controller in Directory Services Restore Mode.
Authoritative restore of SYSVOL
By authoritatively restoring the SYSVOL, you are specifying that the copy of SYSVOL that is restored from backup is authoritative for the domain. After the necessary configurations have been made, Active Directory marks the local SYSVOL as authoritative and it is replicated to the other domain controllers within the domain.
The authoritative restore of SYSVOL does not occur automatically after an authoritative restore of Active Directory. Additional steps are required.
As with Active Directory authoritative restore, you typically perform an authoritative restore of SYSVOL when human error is involved and the error has replicated to other domain controllers. For example, you might perform an authoritative restore of SYSVOL if an administrator has accidentally deleted an object that resides in SYSVOL, such as a Group Policy object.
http://yourcomputer.in/authoritative-vs-non-authoritative-restoration-of-active-directory
How to restore the AD
http://technet.microsoft.com/en-us/library/bb727048.aspx
What is Tombstone period?
The tombstone lifetime in an Active Directory forest determines how long a deleted object (called a “tombstone”) is retained in Active Directory Domain Services (AD DS). The tombstone lifetime is determined by the value of the tombstoneLifetime attribute on the Directory Service object in the configuration directory partition.
In Microsoft Windows Server 2003 R2, the default tombstone lifetime (TSL) value remains at 60 days.
Note In Windows Server 2003 Service Pack 1, the default TSL value has increased from 60 days to 180 days.
What are Lingering Objects?
Lingering objects can occur if a domain controller does not replicate for an interval of time that is longer than the tombstone lifetime (TSL). The domain controller then reconnects to the replication topology. Objects that are deleted from the Active Directory directory service when the domain controller is offline can remain on the domain controller as lingering objects.
What is the difference between 2003 and 2008?
http://yourcomputer.in/difference-between-windows-2003-and-2008/
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.
3) In Windows Server 2008, Microsoft is introducing new features and technologies, some of which were not available in Windows Server 2003 with Service Pack 1 (SP1), that will help to reduce the power consumption of server and client operating systems, minimize environmental byproducts, and increase server efficiency.
Microsoft Windows Server 2008 has been designed with energy efficiency in mind, to provide customers with ready and convenient access to a number of new power-saving features. It includes updated support for Advanced Configuration and Power Interface (ACPI) processor power management (PPM) features, including support for processor performance states (P-states) and processor idle sleep states on multiprocessor systems. These features simplify power management in Windows Server 2008 (WS08) and can be managed easily across servers and clients using Group Policies.
What Is Strict Replication and How Do You Enable?
Strict Replication is a mechanism developed by Microsoft developers for Active Directory Replication. If a domain controller has the Strict Replication enabled then that domain controller will not get “Lingering Objects” from a domain controller which was isolated for more than the TombStone Life Time. TSL is 180 days by default on a Forest created with Windows Server 2003 SP1. A domain controller shouldn’t be outof sync for more than this period. Lingering Objects may appear on other domain controllers if replication happens with the outdated domain controllers. These domain controllers will not replicate with the outdated domain controllers if you have set the below mentioned registry key.You must set the following registry setting on all the domain controllers to enable the Strict Replication:
- KEY Name: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters
- Registry Entry: Strict Replication Consistency
- Value: 1 (enabled), 0 (disabled)
- Type: REG_DWORD
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