User directories
You might be wondering how and where Jira stores users and groups. User directories are what Jira uses to do this. A user directory is backed by a user repository system, such as LDAP, a database, or a remote user management system, such as Atlassian Crowd. Out of the box, Jira comes with a default internal directory that stores user and group information in the database.
You can have multiple user directories in Jira. This allows you to connect your Jira instance to multiple user repositories. For example, you can have an LDAP directory for your internal users and the Jira internal directory using the database for external users. An example is given in the following screenshot, where we have three user directories configured. The first user directory is the built-in Jira internal directory running on the Jira database. The second user directory is connected to Microsoft Active Directory (AD) in read-only mode. The last user directory is connected to Atlassian Crowd...