Every day we experience the power of directory service. Even though it does not directly visible for the end user, lot of applications run on a directory service platform. We can’t think a network without active directory. The influence of active directory is that big. But the question is a little bit different… Why can’t we use other technologies/alternatives instead of active directory? Why do we still use active directory? Have you ever thought of that? Have you ever thought of an alternative for AD?
I had thought of this many times when I was working in the critical role of an active directory enterprise admin of Asia’s Largest Software and IT Company. I am very keen to find out open source alternatives for licensed software. A simple search in Google for the alternatives returned a dozen of them including:
- Novel e Directory
- Red hat/Fedora Directory Server
- Open Directory
- Apache Directory
- Oracle internet directory
- IBM Tivoli Directory Server
- CP directory Server
- Open LDAP
But none of these can actually ‘replace’ active directory. It is a trivial task to find out the best LDAP directory service from the above list if you just require the basic functionalities like Centralized Authentication. With all my experience I can easily pick the better alternative from this list and that is definitely the Novell E Directory. E directory and Active directory are the leading directory services. Novell is there in the directory service market from early 90s. Currently it is in 8th generation. Active directory is also there from 90s but in its top form from the release of Windows 2000 server.
You would consider Scalability, Compatibility, Reliability, Manageability and Security to rate a directory service. I installed and compared E directory and Active directory based on the above categories.
Microsoft itself says a limit for the number objects in active directory. Novell had tested their directory with more than a billion objects in last century. If the number of objects is really massive, no need to think… its e directory.
E directory multi master operation makes it really scalable and reliable. Multi master replication is there in active directory but the FSMO roles make it weaker. When the critical a role like PDC is down, administrator effort is required to seize or transfer the unavailable role. Otherwise the directory functioning will be in trouble. In active directory we cannot have multiple servers with same FSMO role. In E directory there is no FSMO single master concept. This eliminates the criticality of a role holder server.
E Directory uses hierarchical database while active directory uses flat database, therefore, no two entity can be same name in active directory, but it is possible in e Directory, searching speed is more and reliable in e Directory than Active Directory because of hierarchical architecture of e Directory.
For most of the active directory database operation we need to make the server offline and need to bring it into DSRM to perform the recovery operations. In e directory we can do most of the database operations without bringing the server down.
If you want to restore an active directory server for any reasons you could restore it to the last available backup and that may be the last week or last night or as per you backup configuration. The e directory hot continuous backup feature will let you restore the directory to the last moment before the failure.
e directory has some more advantages like, Dynamic Inheritance, Customizable Objects and Security Principles etc. In Active Directory you cannot have a security principal other than a User, Computer or a group. But in E directory, a Container is also considered as a security principal.
The dynamic inheritance in e directory makes the large scale right assignments easier. When you assign a setting to a container with a million objects there are chances of a crash in Active directory as it will write down the changes to the ACLs of individual objects.
Because of the dynamic inheritance, hierarchical manner etc the e directory database will really small when you compare it with an active directory database with same number of objects.
Oh, I missed out the point about interoperability and compatibility… You can host e directory in a variety of operating systems like Windows, Linux and Unix etc. You can have multiple client operating systems as well.
When we check the authentication, the e directory can have multiple authentication methods. We can also configure multiple authentication levels according to the security requirements.
If you do a micro comparison you can find out more and more points to add. But most of them will be in favor of Novell E directory. Novell calls the E directory as the High End directory service and that is true. From the above points we can note that E directory is far better than active directory when you consider the following:
- Scalability: Suitable for huge number of objects and large organizations
- Compatibility: Multiprotocol, Multiplatform
- Reliability: Multi master, self repairing directory service. Live maintenance tools available
- Manageability: We based multi platform management and monitoring tools available
- Security: Multiple authentication levels, multiple platforms and Advanced Security Principals.
Now what do you think? Which one is better? The question is still unanswered. Why we are still using Active directory?
It’s only because of the Wide usage of Windows in corporate world. More than 90 % of the operating system market share is for windows. I would personally like to work in active directory rather than e directory because of the friendly environment. Most of us have Windows servers in our office and there is no extra cost required to purchase Windows AD if you have a windows Server License… Then why do you need to purchase another directory service for some extra rupees?
But if your requirement is really a serious and huge one you need think twice