Having Multiple UserProfile Sync services
In an architecture I worked on I was isolating two service groups , I wanted to isolate a service group that service some SP Applications from others , with security , information leakage and other concerns in mind ( like having own managed metadata services , and profile services etc.)
The problem was having two or More UserProfile Synchronization services, While many might say , why , and you don’t need another one , or it can’t be done.
Simply the problem is that User Profiles are always tied to the mySite host and that is a global configuration setting on the service application (your first provisioned UPS application ).
The opted design:
You can have multiple UserProfile Sync services but they can each reside on a single SharePoint hos within your farm.
You cannot have multiples on the same host , as it is simply a Forefront Identify management engine ( Geneva ) and given the complexity of this thing , I would not even think about running two of them on the same host.
The main problem :
After declaring success on this front and having the two sync service application , each with multiple and different AD connections , I noticed that the sync works fine , to all sites and content . yet the farm backup job fails sporadically with this error on the log.
[8/21/2013 9:11:08 PM] FatalError: Object SP-USER-PROFILE-SERVICE failed in event OnBackup.
For more information, see the spbackup.log or sprestore.log file located in the backup directory.
SPDuplicateObjectException: An object of the type Microsoft.Office.Server.Administration.ProfileSynchronizationUnprovisionJob
named “ProfileSynchronizationUnprovisionJob” already exists under the parent Microsoft.SharePoint.Administration.SPTimerService named “SPTimerV4”. Rename your object or delete the existing object.
The main solution:
The cause of the problem is the incremental backup that took longer than usual and got into the AD Sync cycle of one of the Sync Services.
The solution is simple, Stop both SYNC services, start both sync services ( on each respective server) , push the backup window a few hours apart.
That solved my problem. Hope is solves yours.
Best of Luck