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70-294: MCSE Guide to Microsoft Windows Server 2003 Active Directory, Enhanced Chapter 4: Active Directory Architecture. Objectives. Describe the underlying database of Active Directory Describe the Active Directory schema and how it can be extended
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70-294: MCSE Guide to Microsoft Windows Server 2003 Active Directory, EnhancedChapter 4: Active Directory Architecture
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 70-294, Enhanced
Active Directory Physical Database Storage • Layers • Provide the directory service • Include: • Extensible Storage Engine (ESE) • Database layer • Directory Service Agent (DSA) Guide to MCSE 70-294, Enhanced
Active Directory Layers Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
Active Directory File Structure • Files: • NTDS.DIT • EDB.LOG • EDBXXXXX.LOG • EDB.CHK • RES1.LOG and RES2.LOG • TEMP.EDB Guide to MCSE 70-294, Enhanced
Active Directory Files Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
EDB.CHK • Checkpoint file • System recovering from failure • Uses EDB.CHK file to determine what transactions should be written to database Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
TEMP.EDB • Temporary storage space • Hold large transactions while they are in process • Used during maintenance operations Guide to MCSE 70-294, Enhanced
LDAP • Primary protocol used to work with objects in Active Directory • Vital to understand how to use LDAP naming paths Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
Naming • Every object class and attribute in the schema must have: • Unique common name • LDAP display name • Object Identifier (OID) Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
Example common names and LDAP display names Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
Common Syntaxes Guide to MCSE 70-294, Enhanced
Common Syntaxes (continued) Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
Active Directory Partitions (continued) Guide to MCSE 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 70-294, Enhanced
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 Guide to MCSE 70-294, Enhanced