After populating Active Directory and Directory Server with users and installing the Active Directory and Directory Server Connectors (before starting synchronization), you must use the idsync resync command to ensure that all existing users are linked in the two directory sources.
What is linking? Identity Synchronization for Windows correlates the same user on Directory Server and on Windows by storing the following unique, immutable identifiers:
Storing this immutable identifier allows Identity Synchronization for Windows to synchronize other key identifiers, such as uid and cn. The dspswuserlink attribute is populated when:
Identity Synchronization for Windows creates a new user in Directory Server (after a new user is synchronized from Windows or by runningidsync resync -c)
Identity Synchronization for Windows creates a new user on Windows (after synchronizing a new user from Directory Server or by running idsync resync -c -o Sun)
You run idsync resync -c -f to link entries that already exist on Directory Server and Windows as described in this chapter.
To link existing users, you must provide rules for matching users between the two directories. For example, to link a user entry in two directories, both the first names and last names must match in both directory entries.
Linking user entries and resolving data conflicts could be described as more art than science. There are many reasons why the idsync resync subcommand might fail to link two users in opposing directory sources and depends to a large extent on the consistency of the data in the linked directories.
One strategy for using idsync resync is to use the -n argument, which runs the operation in “ safe mode” so you can preview the effects of an operation with no actual changes. Running in safe mode allows you to refine the linking criteria gradually until you find an optimum set of user matching criteria.
However, you should be aware that there is a balance to be achieved through linkage accuracy and linkage coverage.
For example, if both directory sources contain an employee ID or social security number, you might begin with linking criteria that includes this number only. You might think that to improve linkage accuracy, you should include a last name attribute in the criteria as well. However, you could lose linkages because entries that would have matched on ID alone did not match because there were inconsistent last name values in the data. You will have to go through a data cleansing process for entries that fail to link.
If Group Synchronization is enabled then the groups are linked in the same way as the users are linked.