An object set may be redundantly stored by a set of computers, each configured to store a local representation of corresponding objects. When a computer changes the object set (e.g., by adding or altering an object), the updated object may be synchronized across the computers by iteratively forming and using an ad hoc swarm network from the neighbors of a node storing the updated object. This swarm network may operate cooperatively, where each node distributes object chunks to other nodes as quickly as possible, and may disregard concepts of competitive swarm networks such as fairness and cheating avoidance, which may not apply to cooperative swarming and might otherwise slow the propagation of the object. An alternative “ask” technique may be included to identify and recover missed object updates, and a computing environment host may be included as an authoritative object source and/or as an object store of last resort.