US Patent 11681443 Durable data storage with snapshot storage space optimization

A data storage system includes a head node and mass storage devices. The head node is configured to store volume data and flush volume data to the mass storage devices. Additionally, the head node is configured to determine a quantity of data partitions and/or parity partitions to store for a chunk of volume data being flushed to the mass storage devices in order to satisfy a durability guarantee. For chunks of data for which complete copies are also stored in an additional data storage system, the head node is configured to reduce the quantity of data partitions and/or parity partitions stored such that required storage space is reduced while still ensuring that the durability guarantee is satisfied.