- Set Server1 as “first target among equal cost”.
- Set Server2 as “last target among equal cost”.
- Enable Fail-Over on DFS namespace.
- Server3 should in a different site. So the site cost should always larger than onsite target. By default it will be the last option in choosing referral target.
Note: It will still have some delay before client getting a new referral target as client will cache the target for a while. You can change the Duration time shorter.