When to use LDAP over a database?

Question

When should I use LDAP vs. database/key-value-store/column-oriented-database/etc?

Answer 1

In the past, certainly, and with directory servers that are descended from the Univ. of Mich. code base, write-once read-many was certainly the case, and directory servers descended from that code base suffer from poor write performance. Over the years, though, LDAP users have demanded increased write performance and transactional qualities from LDAP directory servers and modern Java-based directory servers have excellent read and write performance.