Abstract: A method comprising: prior to performing a planned i-th data movement in a distributed data system comprising a plurality of storage sites, generating (i) a first map of current locations of data item replicas following an immediately-preceding (i?1)-th data movement, (b) a first timestamp associated with a completion of said (i?1)-th data movement, and (c) a second map of expected locations of data item replicas following said i-th data movement; implementing said i-th data movement; generating, upon performing said i-th data movement, a second timestamp associated with a completion of said i-th data movement, wherein said second timestamp is indexed as i; and if a failure occurs with respect to at least one of said storage sites during said i-th data movement, determining a completion status of said i-th data movement, based on a comparison between said indexing of said second map and said indexing of said second timestamp.

Abstract: Systems and methods are provided for moving replicas of a target data object between a plurality of storage nodes that store multiple replicated data objects, by setting new applications to a move mode, waiting for prior applications to exit before moving the target data object, determining that an indication of access to the target data object is done, and responsively copying the replicas of the target data object from first locations among the plurality of data storage nodes to second locations among the plurality of storage nodes.

Abstract: A method comprising: prior to performing a planned i-th data movement in a distributed data system comprising a plurality of storage sites, generating (i) a first map of current locations of data item replicas following an immediately-preceding (i?1)-th data movement, (b) a first timestamp associated with a completion of said (i?1)-th data movement, and (c) a second map of expected locations of data item replicas following said i-th data movement; implementing said i-th data movement; generating, upon performing said i-th data movement, a second timestamp associated with a completion of said i-th data movement, wherein said second timestamp is indexed as i; and if a failure occurs with respect to at least one of said storage sites during said i-th data movement, determining a completion status of said i-th data movement, based on a comparison between said indexing of said second map and said indexing of said second timestamp.

Abstract: Systems and methods are provided for moving replicas of a target data object between a plurality of storage nodes that store multiple replicated data objects, by setting new applications to a move mode, waiting for prior applications to exit before moving the target data object, determining that an indication of access to the target data object is done, and responsively copying the replicas of the target data object from first locations among the plurality of data storage nodes to second locations among the plurality of storage nodes.