Patent attributes
A data storage system includes a head node and mass storage devices. The head node is configured to flush data stored in a storage of the head node, based at least in part on one or more triggers being met, from the storage of the head node to a set of the mass storage devices of the data storage system. The flushed data is written to a segment of free storage space across the set of the mass storage devices allocated for the given data flush operation. In some embodiments, a head node may flush both current version data and point-in-time version data to the set of mass storage devices. Also, the data storage system maintains an index that indicates storage locations of data for particular portions of a volume before and after the data is flushed to the set of mass storage devices.