A method, system, computer system, and computer program product to quickly synchronize replicas of data stored at multiple secondary nodes upon failure of a primary node. Secondary nodes to which an update to data in a region of a storage area is sent are identified. When all of the secondary nodes have acknowledged the update, a notification is sent to each of the secondary nodes. Respective indicator(s) (e.g., “outstanding update” or “out of sync” indicators) can be set to indicate that the data have changed in respective region(s) at one of the secondary nodes when the update has been received at that secondary node. The indicator(s) can be reset for the respective region(s) when the notification sent by the primary node is received at the secondary node. Data in the region(s) can be synchronized with data at secondary nodes when either node has an indicator set for that region.