Hub-to-Branch Office Replication Overload (Outbound Overload)
Applies To: Windows Server 2008
Outbound overload occurs when too many branch office domain controllers are attempting to pull changes from a hub site bridgehead server at the same time. Replication from bridgehead servers to read-only domain controllers (RODCs) can create an outbound overload condition. This situation can occur in two ways:
The connection objects are unbalanced, and too many of them point to a single bridgehead server. RODCs automatically balance connection objects. However, if you have writable domain controllers in branch offices in addition to RODCs, connection objects can become unbalanced.
The replication schedule is too aggressive so that replication never finishes. This happens because some high-priority updates always take precedence in the replication queue and lower-priority updates never replicate.
You can resolve the problem of outbound overload by using the same methods that you use for inbound overload: extend the availability schedule, add another bridgehead server in the hub site, or use the Adlb.exe tool to rebalance connections within the site. As an alternative, you can consider switching to better hardware with multicore processors so that more threads can be run in parallel.
For File Replication Service (FRS) replication, the outbound connections on the bridgehead servers must be monitored for increased backlog. For more information, see Monitoring Your Branch Office Environment.