Efficient Scheduling of Data Transfers in Multi-Tiered Storage

Multi-tiered persistent storage systems integrate many types of persistent storage devices, such as different types of NVMes, SSDs, and HDDs. This integration provides a multi-level view of persistent storage, where each tier has a different data transmission speed and capacity. Data transfer processes operating on multi-tiered persistent storage allow for the parallelisation of data transfers among the partitions of data at the same or different tiers. This work considers the problem of efficient scheduling of parallel data transfers between the tiers of persistent storage. We consider a data processing model where several data transfer processes move or copy data from one tier to another through the buffers in transient memory. We propose a new model for data processing over multi-tiered persistent storage and new algorithms to minimise both the overall time spent on parallel data transfers and the idle time of data transfer processes. We also describe how the scheduling algorithms dynamically apply different procedures to assign data transfers to the processes. Finally, we present the outcomes from the experiments that confirm the correctness and efficiency of the scheduling algorithms.