Risk based rebuild of data objects in an erasure coded storage system

A rebuild node of a storage system can assess risk of the storage system not being able to provide a data object. The rebuild node(s) uses information about data object fragments to determine health of a data object, which relates to the risk assessment. The rebuild node obtains object fragment information from nodes throughout the storage system. With the object fragment information, the rebuild node(s) can assess object risk based, at least in part, on the object fragments indicated as existing by the nodes. To assess object risk, the rebuild node(s) treats absent object fragments (i.e., those for which an indication was not received) as lost. When too many object fragments are lost, an object cannot be rebuilt. The erasure coding technique dictates the threshold number of fragments for rebuilding an object. The risk assessment per object influences rebuild of the objects.