I recently had an issue on a customer site whereby the Active Directory and in particular the View Pools sync in VMware Identity Manager were taking a long time. The customer had domain controllers worldwide and the issue was that vIDM was using a remote domain controller with high latency for its actions.
To fix this i specified the domain controllers to use with in the appliance by following the following kb
The kb walks you through creating a domain_krb.properties file where you can specify the Domain Controllers to use. This also works with aliases such as domaincontrollershq.example.com
Remember to restart the services and to make this change on all the nodes in your cluster or preferably before you clone it out.