102 5.2 Directory Services
Google and Amazon. Most large organizations can perform all of the
actions in the previous chapter, and many of those in this one.
For very small organizations, open source systems may be installed
where they had nothing in place before. For organizations in between, the
situation may be more difficult. For mid-sized companies, the option of
allowing one supplier to do the integration can be an attractive business
proposition. For companies of $100M or so, this may mean purchasing all
systems from one supplier, such as Microsoft, and allowing that integration
to simplify their operations. For companies in the billions, where IT is not a
core asset, this may mean hiring companies such as IBM Global Services or
EDS and outsourcing operations.
5.2 Directory Services
The biggest cost benefit from infrastructure migration often comes from
eliminating the directory element from Windows, since the client access
license (CAL) for directory access is the most expensive software element of
file storage. This also has a benefit in reduction of lock-in, as an open direc-
tory will support many different products from many vendors. The best
argument for OpenLDAP is that the directory, touching so many systems
and containing your proprietary information, is a very logical place to
maintain open standards.
The choices for directory services are the open source OpenLDAP and
closed code products, including:
Novell eDirectory
Sun ONE Directory Server
IBM Directory Server
Microsoft Active Directory
All of these are expensive compared with OpenLDAP. Microsoft Active
Directory will not run on Linux, but it can support other servers and clients
as an LDAP directory, so it deserves to be included. In some strategies, we
will continue to use Active Directory and another directory server in a
mixed infrastructure environment, and we will want them to work together.
We will need to survey the organization to find out what aspects of the
directory people really use. This is certainly the case if Active Directory or

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