US Patent 10896006 Log-structured storage systems

Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage devices, for data processing. One of the methods includes maintaining, by a storage system, a plurality of storage devices that include at least a first tier storage device and a second tier storage device. The storage system receives a write request of a ledger data, determines whether a type of the ledger data is block data, and, in response to determining that the type of the ledger data is block data, writes the ledger data into the second tier storage device.