Optimizing Stream Separation Using Event Logs in FDP Storage Devices

The new Non-Volatile Memory express (NVMe) specification, Flexible Data Placement (FDP), introduces a method for improving storage efficiency and performance by reducing the write amplification and ensuring quality of service (QoS). FDP allows hosts to place data into the desired block by specifying the stream in write command. Hosts can reduce write amplification by placing data with similar lifetime in the same block. Additionally, FDP also ensures that each VM uses a different physical die group to minimize performance interference between VMs as much as possible. FDP also has four FDP-specific log pages, of which the Media Reallocated event in the FDP events log was used to experiment with reducing the WAF by reallocating streams by hosts that incorrectly predicted the lifetime of data. Experiments show that this method could significantly reduce the garbage collection cost to almost zero.