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This chapter is from the book

This chapter is from the book

Understanding eDirectory 8.6

Test Objectives Covered:

  1. Identify the role and benefits of eDirectory (continued).

  2. Identify how eDirectory 8.6 works.

  3. Identify and describe the composition of eDirectory.

eDirectory 8.6 is a highly scalable, high-performing, secure Directory service. Along with replication and partitioning capabilities, eDirectory provides the basic foundation for multiplatform networking. eDirectory also includes cryptography services to protect confidential data; it natively supports LDAP 3 over Secure Socket Layer (SSL).

Although all NetWare 6 servers on the network use the Directory, you probably don't want to store a complete copy of it on each server. This is particularly true if you have a large network. Fortunately, NetWare 6 enables you to break up the Directory into smaller pieces called partitions and replicate them on multiple servers. This means that any NetWare 6 server can contain a copy of the entire Directory, specific pieces of it (partitions), or none at all. Of course, it's best to keep copies of important partitions closest to the users who need them. This minimizes unnecessary replica synchronization and background network traffic.

Features and Benefits of eDirectory 8.6

Following are some reasons why I think eDirectory is the greatest thing since sliced bread:

  • eDirectory offers a global database for central access and management of network information, resources, and services.

  • eDirectory offers a standard method of managing, viewing, and accessing network information, resources, and services.

  • eDirectory enables you to logically organize your resources independent from their physical characteristics or layout of the network.

  • eDirectory provides dynamic mapping between an object and the physical resource to which it refers.

  • eDirectory works today and is several years ahead of any competitor with proven reliability, scalability, and security for enterprise networks.

  • eDirectory significantly lowers the cost of managing and administering a network through centralized access and management of all network and operating system resources. In addition, it significantly lowers the cost of connectivity and data synchronization over a wide area network.

The eDirectory architecture, which you'll examine in detail later in this section, provides an exceptional foundation for all of eDirectory 8.6's new features and benefits.

Following is a brief list of some of eDirectory's greatest new advancements:

  • eDirectory 8.6 can be implemented on any of these operating system platforms: NetWare, Windows NT, Windows 2000, Linux, Solaris, and Tru64 UNIX. Client libraries and LDAP tools are available for Linux, Solaris, and Tru64 UNIX. LDAP support provides an open structure for integration with applications that are written to the LDAP standard.

  • The Index Manager tool enables you to manage database indexes easily. The Filtered Replica Configuration Wizard enables you to easily create filtered replicas, which are replicas that contain a filtered list of network resources.

  • The eDirectory Import/Export Wizard enables you to import or export LDIF files and to perform a server-to-server data migration.

  • eDirectory includes a merge utility that enables you to merge one directory tree into another or to graft one tree onto another.

  • iMonitor provides monitoring and diagnostic capabilities for all servers in your eDirectory tree from a Web browser.

  • ConsoleOne provides you with a utility to manage eDirectory users, objects, schema, partitions, and replicas.

Some of the major benefits of eDirectory are as follows:

  • Central management of network information, resources, and services

  • Standard method of managing, viewing, and accessing network information, resources, and services

  • Logical organization of network resources that are independent of the physical characteristics or layout of the network

  • Dynamic mapping between an object and the physical resource to which it refers

The Role of eDirectory

When a NetWare client (such as a user, application, or server) requests access to a network resource or service, eDirectory satisfies the request according to data stored in the network-wide Directory. One of the advantages of this strategy is that client requests are separated from resource physicality—that is, users don't need to know where a physical resource is located. They simply reference its unique Directory name. Because all NetWare 6 servers provide eDirectory, any NetWare 6 server on the same network can connect you with the resource.

The following list describes how eDirectory processes client requests:

  1. The user logs in via a NetWare 6 client and establishes credentials and signature. A credential is a data structure such as a network address, time of login, username, and password. It consists of a validation period and other identification information. A signature is the result of encryption of this data.

  2. The NetWare 6 client requests a service that has been requested by a user or application. The service responds by sending the client a random number generated for the current transaction only. (The random number is not used again.)

  3. Using the signature, the client provides proof that the credential and random number are correct.

  4. The client sends the random number, the credential, and the signature to the service.

  5. Client validity and authority are checked by verifying that the proof was legitimately generated from the random number and credential. The random number ensures that the request was created from the current session.

  6. The service returns a confirmation.

  7. The client is then connected to the resource.

Earlier versions of eDirectory were called Novell Directory Services (NDS). At first glance, eDirectory appears to have the same underlying architecture as NDS—that is, a distributed, object-oriented database organized as a hierarchical tree. Upon closer inspection, however, you'll find that eDirectory 8.6 is built on a much more sophisticated database structure than NDS.

Let's take a closer look at the underlying architectural differences between NDS and eDirectory, starting with NDS.

NDS Architecture

NDS was first introduced in NetWare 4. Prior to NetWare 4, NetWare operating systems relied on a server-centric model in which each NetWare server had its own flat-file database for tracking network resources (called the Bindery). The bindery consisted of three files: one that held objects, one that held property, and one that held value information.

NDS offered a gigantic leap forward by evolving the server-centric model into a network-centric model. In this architecture (shown in Figure 3.3), the NetWare 4 operating system relies on four data files and multiple streams files located in a hidden directory on the server's SYS: volume. This database is called the RECMAN database.

Figure 3.3Figure 3.3 NDS architecture.

The four files that make up the NDS architecture in Figure 3.3 perform the following functions:

  • PARTITIO.NDS—The partition database contains a list of database partitions including system, schema, external reference, and bindery.

  • ENTRY.NDS—The object database contains records for each object in a given server's replicas.

  • VALUE.NDS—The attribute database contains property values for each object in ENTRY.NDS.

  • BLOCK.NDS—The block database contains overflow data for the attribute database.

NDS streams files are named with hexadecimal characters (0–9, A–F) and hold information such as print job configurations and login scripts. Earlier versions of NDS used Novell's Transactional Tracking System (TTS) to ensure that database transactions were either completed or backed out in the event of a system failure.


The NetWare 5 version of NDS uses the same architecture as described previously; however, the names of the files are different. In NetWare 5, ENTRY.NDS is called 0.DSD, VALUE.NDS is called 1.DSD, BLOCK.NDS is called 2.DSD, and PARTITIO.NDS is called 3.DSD.

eDirectory 8.6 Architecture

eDirectory 8.6 improves on NDS's fixed-length record data store model by introducing a highly scalable indexed database called the FLexible and Adaptable Information Manager (FLAIM). The FLAIM database uses three types of files instead of four, but still relies on streams files for print job configurations and login scripts. Check out the eDirectory 8.6 architecture shown in Figure 3.4.

Figure 3.4Figure 3.4 eDirectory 8.6 architecture.

Following is a description of each of the three types of files that make up eDirectory's FLAIM database:

  • NDS.DB—The control file is the centerpiece of the eDirectory architecture. This file contains the rollback log and is used to abort incomplete transactions.

  • NDS.01—The primary database file contains all records and indexes found on a given server. When this data file reaches 2GB in size, NDS.02 is created for the remaining data. New files are then created as necessary to keep database files from growing beyond 2GB. This allows the database files to remain scalable while retaining their quick search capabilities.

  • NDS*.LOG—The transaction log file acts as a roll-forward log to reapply completed transactions that might not have been fully written to disk because of a system interruption.

eDirectory streams files perform the same function that they do in NDS and have an .NDS extension. However, unlike NDS, eDirectory does not use TTS; instead, it uses log files to back out and roll forward transactions in the event of a system failure. Refer to Table 3.1 for a summary of the differences between NDS and eDirectory architecture.


The primary eDirectory database file, NDS.01, includes a number of indexes to enhance performance. First, it includes attribute substring indexes for the CN and uniqueID fields. Second, it includes attribute indexes for the Object Class and dc fields. Finally, it includes attribute indexes for positioning that include strings beginning with CN, uniqueID, Given Name, and Surname.

Table 3.1 Comparing NDS and eDirectory Architecture




Database Name



Database Function Data Store

Fixed-Length Record Indexed Database

Highly Scaleable

NetWare Version

4.x and 5.x


Number of Files



Data Records File



Rollback Mechanism


Log Files




This completes the architectural lesson of eDirectory 8.6. We hope that you have gained an appreciation for the sophisticated directory services platform that eDirectory 8.6 provides for your NetWare 6 network. Now that you understand how it's built, you're ready to learn how to integrate it into your existing network.

Now that you understand the fundamental architecture of eDirectory, the next sections take a closer look at its different container and leaf objects. These are the physical foundation of the logical eDirectory tree.

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