"In a heterogeneous data center, administering access and
managing identity can be time-consuming any way you slice it. With
user data scattered within metadirectories or elsewhere in a
company, creating single sign-on techniques for disparate data is
vexing for many IT departments.
"Further complicating things, solutions for Linux authentication
in heterogeneous data centers are legion. Finding the right fit can
be as difficult as managing the problem itself. And as system
administrators weigh the options, a central question is, Do any of
the alternatives trump Microsoft's Active Directory (AD)...?"