Understanding Domains, Active Directory, and RAID Configurations

Posted on Nov 13, 2024 in Computers

Domain

A domain is a set of user accounts and network resources under a single name, establishing security boundaries. Active Directory, installed on a Windows Server, manages the domain. Servers within a domain can be:

  • Domain Controllers: These servers belong to the domain and hold a copy of user accounts and other Active Directory data. At least one domain controller is required.
  • Member Servers: These servers store files and other network resources.

Workgroup

A workgroup is a basic grouping that allows users to share resources. Workgroup users typically use local passwords, while domain users use domain passwords for network access.

Active Directory

Active Directory is a directory service built into Windows. It includes:

  • Directory: A data warehouse storing information about objects.
  • Schema: A set of rules defining object classes, attributes, restrictions, and limits within the directory.
  • Global Catalog: Contains information about every object in the directory.
  • Replication Service: Distributes directory data across the network. All domain controllers participate in replication and maintain a complete copy of the directory information.

The Active Directory structure includes domains, forests, trees, organizational units, groups, and objects.

Key features include:

  • Automatic establishment of transitive and bidirectional trust relationships within a domain tree.
  • Support for inheritance.
  • Flexible administration privileges.

User Types

  • Global Users: Accounts created on domain controllers.
  • Local Users: Accounts created on computers that are not domain controllers. These users cannot connect to a domain.

Profile Types

  • Mobile Profile: User modifications are saved and persist after the connection ends.
  • Required Profile: User modifications are lost after the connection ends.

Access Profile and UNC Path

  • Access Profile: Specifies the network path for a user’s roaming or mandatory profile.
  • UNC Path: A standardized format for specifying network resource locations. The format is \\server-name\path-of-resource-sharing.

System Variables

System variables are small memory allocations with assigned values (numbers, directory paths, etc.). There are three types:

  • Environment Variables: Part of the system environment, provided by the system, and cannot be modified.
  • System Variables: Built-in variables that cannot be modified by programs or the shell.
  • User Variables: Can be modified by the user.

Striping and RAID

Striping combines multiple physical disks into one logical disk, partitioning data to improve performance.

RAID (Redundant Array of Independent Disks) stores data redundantly across multiple hard drives to improve performance and fault tolerance.

RAID Levels

  • RAID 0: Data is striped across multiple disks for performance, but lacks redundancy.
  • RAID 1: Data is mirrored across two disks for redundancy.
  • RAID 2: Uses striping with error correction codes.
  • RAID 3: Parallel disks with a dedicated parity disk.
  • RAID 4: Independent disks with a dedicated parity disk.
  • RAID 5: Data and parity are striped across multiple disks.
  • RAID 6: Similar to RAID 5 but with dual parity for increased fault tolerance.
  • RAID 7: Includes a real-time operating system as a controller.
  • RAID 10 (RAID 1+0): Combines striping (RAID 0) and mirroring (RAID 1).
  • RAID 30: Combines striping (RAID 0) and dedicated parity (RAID 3).
  • RAID 50: Combines striping (RAID 0) and distributed parity (RAID 5).

Links:

  • Symbolic Links: Pointers to files or directories. Deleting the target breaks the link.
  • Hard Links: Create copies of files or directories. Changes to one affect the other.