Abstract: Embodiments of the present disclosure relate to method, device and computer program product for data backup. The method comprises: in response to receiving from a backup server a data stream to be backed up, dividing the data stream into a plurality of data segments; distributing the plurality of data segments to at least one computing node; in response to receiving an index of a corresponding data segment from a first computing node of the at least one computing node, looking up the index in a global index cache, the index being generated by the first computing node to uniquely identify the data segment, the global index cache storing indexes of data in a backup storage device; in response to the missing index in the global index cache, adding the index into the global index cache; and sending to the first computing node an indication to store the data segment in the backup storage device.

Abstract: A system of synchronized computing devices, connected via a common network and configured to operate one or more common computing tasks across the system, includes a plurality of subcomponent computing devices, each including, at least, a non-transitory, machine readable storage medium, storing instructions associated with the one or more common computing tasks. The system further includes one or more processors, each of the processors configured to output a plurality of events occurring throughout the system. The system further includes a synchronization controller configured to determine a continually updating value of interest, based on a symmetric function of the one or more events, provide the continually updating value of interest, subject to a time delay, wherein the time delay is a time period having a length substantially longer than an average time interval between two consecutive members of the plurality of events.