70-294: MCSE Guide to Microsoft Windows Server 2003 Active Directory, Enhanced Chapter 4: Active Directory Architecture

Guide to MCSE , Enhanced2 Objectives Describe the underlying database of Active Directory Describe the Active Directory schema and how it can be extended Describe the different Active Directory partitions and their functions

Guide to MCSE , Enhanced3 Active Directory Physical Database Storage Layers Provide the directory service Include: Extensible Storage Engine (ESE) Database layer Directory Service Agent (DSA)

Guide to MCSE , Enhanced4 Active Directory Layers

Guide to MCSE , Enhanced5 Active Directory Physical Database Storage Extensible Storage Engine: Lowest level Directly responsible for manipulating database All objects stored in nonhierarchical form Rows in database table Database layer: Responsible for providing object-oriented hierarchical view

Guide to MCSE , Enhanced6 Active Directory Physical Database Storage (continued) Directory Service Agent: Third layer Responsible for enforcing semantics Govern how objects in Active Directory are created and manipulated Only adjacent layers communicate with one another

Guide to MCSE , Enhanced7 Extensible Storage Engine Active Directory store: Transactional database Based on Extensible Storage Engine Transaction Each addition, modification, or deletion Needed data is loaded from disk to memory

Guide to MCSE , Enhanced8 Extensible Storage Engine (continued) Transaction First thing that happens: Operation is logged to hard disk Modification transaction performs made to the in- memory copy of data Manipulating in-memory copy of data is faster that going to disk

Guide to MCSE , Enhanced9 Extensible Storage Engine (continued) Least recently used: Storing entire database in memory is not practical Move data that is no longer needed Write changes back to hard drive Least recently used algorithm to write to disk: When memory is running low System is at a period of low activity

Guide to MCSE , Enhanced10 Extensible Storage Engine (continued) Transactions: ESE writes all transactions to log before they are made to in-memory copy Next time domain controller starts, ESE can use transactions recorded in log Reapply changes to copy of data stored on hard disk Called recovering the database Done without user intervention

Guide to MCSE , Enhanced11 Extensible Storage Engine (continued) Checkpoints: Shorten recovery times Reduce amount of hard drive space logs take up Completed transactions written back to disk Fact that transactions were successfully written is noted ESE only needs to reapply transactions from point of last checkpoint Transactions can be deleted from log

Guide to MCSE , Enhanced12 Active Directory File Structure Files: NTDS.DIT EDB.LOG EDBXXXXX.LOG EDB.CHK RES1.LOG and RES2.LOG TEMP.EDB

Guide to MCSE , Enhanced13 Active Directory Files

Guide to MCSE , Enhanced14 NTDS.DIT Actual Active Directory store Stores all objects and their attributes Located in %SYSTEMROOT%\ NTDS folder on domain controllers Made up of three tables: Schema table Data table Link table

Guide to MCSE , Enhanced15 EDB.LOG Current transaction log file Changes to Active Directory are noted first in transaction log file Size of EDB.LOG is always 10 MB

Guide to MCSE , Enhanced16 EDBXXXXX.LOG When EDB.LOG is filled, it is renamed to EDBXXXXX.LOG XXXXX is a number increased by one each time a new log file is created Every 12 hours: Garbage-collection process runs Deletes old EDBXXXXX.LOG

Guide to MCSE , Enhanced17 EDB.CHK Checkpoint file System recovering from failure Uses EDB.CHK file to determine what transactions should be written to database

Guide to MCSE , Enhanced18 RES1.LOG and RES2.LOG Placeholder files Reserve disk space If domain controller runs out of free disk space, uses reserved space from files Prevents updates from being lost due to insufficient disk space Important: Include additional free space to store Active Directory database as it grows

Guide to MCSE , Enhanced19 TEMP.EDB Temporary storage space Hold large transactions while they are in process Used during maintenance operations

Guide to MCSE , Enhanced20 LDAP Primary protocol used to work with objects in Active Directory Vital to understand how to use LDAP naming paths

Guide to MCSE , Enhanced21 LDAP (continued) DN: Every object in Active Directory has unique name Describes exactly where the object is located in the object hierarchy Made up of: Name of the object All of parent objects above it in hierarchy

Guide to MCSE , Enhanced22 LDAP (continued) RDN Identifies object within its container Contains only name of object Acronyms for object names: DC (Domain Component) Part of a domain name OU (Organizational Unit) Name of an organizational unit CN (Common Name) Name of most objects

Guide to MCSE , Enhanced23 LDAP (continued) Name example: Lori Thompson located in dev.supercorp.net domain in Research organizational unit DN: CN=Lori Thompson,OU=Research,DC=dev,DC=supercorp,DC= net RDN: CN=Lori Thompson

Guide to MCSE , Enhanced24 Active Directory Schema All available objects and attributes Sets out exactly: What kind of objects are represented What properties or attributes are required or optional What types of values are acceptable Tool needed to modify the schema is not available by default

Guide to MCSE , Enhanced25 Activity 4-1: Registering Active Directory Schema Console Objective: Register the Active Directory Schema snap-in so you can view and modify the schema Follow instructions to register the console

Guide to MCSE , Enhanced26 Naming Every object class and attribute in the schema must have: Unique common name LDAP display name Object Identifier (OID)

Guide to MCSE , Enhanced27 Common Name Rules Start name with registered DNS name of company Separate each level of DNS name with hyphens (-) instead of periods Add another hyphen (-) at end of company’s name Enter current year Follow year with another hyphen (-)

Guide to MCSE , Enhanced28 Common Name Rules (continued) Choose product-specific prefix Must be unique within company Identifies product or application of class or attribute Should begin with uppercase letter with additional letters using capitalization of your choice Follow product-specific prefix with hyphen (-) Enter name of class or attribute separated by hyphens

Guide to MCSE , Enhanced29 LDAP Display Name Rules Start with common name already created for class or attribute Make first character of product-specific prefix lowercase Characters following first character may be uppercase or lowercase

Guide to MCSE , Enhanced30 LDAP Display Name Rules (continued) Make every character in class or attribute part of name that is preceded by a hyphen (-) uppercase Remove all hyphens (-) after product-specific prefix

Guide to MCSE , Enhanced31 Example common names and LDAP display names

Guide to MCSE , Enhanced32 OID OID space must be obtained separately Not part of registered DNS domain name Two primary ways to obtain an OID space: Through Microsoft International Standards Organization (ISO)

Guide to MCSE , Enhanced33 Object Classes Definition of each type of object Like a template from which objects are created Inheritance Class Types: Structural classes Abstract classes Auxiliary classes 88 classes

Guide to MCSE , Enhanced34 Object Classes (continued) Possible superiors Controls which types of objects new object can be instantiated or moved under Example: user object cannot be created (or moved) under a printer object

Guide to MCSE , Enhanced35 Activity 4-2: Creating a Structural Class Objective: Learn how to extend the Active Directory schema to include additional classes Use Active Directory Schema to create a new class

Guide to MCSE , Enhanced36 Attributes Schema contains list of all possible attributes Class is assigned both mandatory and optional attributes Object is sum of its attributes Syntaxes Defines data type attribute can store

Guide to MCSE , Enhanced37 Common Syntaxes

Guide to MCSE , Enhanced38 Common Syntaxes (continued)

Guide to MCSE , Enhanced39 Indexes Similar in concept to index in back of book Store values (in order) for all objects that have a given attribute Speed up queries Slow down creation of objects and updating of attributes Choose attributes that have highly unique values

Guide to MCSE , Enhanced40 Activity 4-4: Adding an Optional Attribute to a Class Objective: Learn how to add additional attributes to a class Use the Schema console to add an attribute to a class

Guide to MCSE , Enhanced41 Active Directory Partitions Database divided into groups called partitions, or naming contexts Used to manage replication Partitions: Schema partition Domain partition Configuration partition Application partition

Guide to MCSE , Enhanced42 Active Directory Partitions (continued) ADSI Edit: Included with Windows Server 2003 Support Tools Used to view and modify objects in various Active Directory partitions

Guide to MCSE , Enhanced43 Active Directory Partitions (continued)

Guide to MCSE , Enhanced44 Schema Stores schema Contains definitions of all classes and attributes in entire forest Replicated to all domain controllers in forest Content is the same throughout forest

Guide to MCSE , Enhanced45 Configuration Stores information about replication topology used in forest Specifies how domain controller determines with which other specific partners it replicates Found on all domain controllers Same throughout forest

Guide to MCSE , Enhanced46 Domain Contains users, computers, groups, and organizational units created in Windows domain Replicated to all domain controllers in domain Large amount of data Usually partition that changes most frequently

Guide to MCSE , Enhanced47 Application Cannot contain security principals Can be replicated to many different domains in forest Without necessarily being included on all domain controllers Used when developer wants to store information in Active Directory

Guide to MCSE , Enhanced48 Summary Active Directory is made up of several layers: Extensible Storage Engine (ESE), Database layer Directory Service Agent (DSA) By logging all transactions, ESE can reapply transactions in event of system failure and bring data back to a consistent state

Guide to MCSE , Enhanced49 Summary (continued) All objects and attributes available in Active Directory are defined in Active Directory schema To effectively manage replication of Active Directory, database is divided into groups called partitions