Data storage system, process and computer program for such data storage system for reducing read and write amplifications

A method in a data storage system connectable to one or more client computers, the data storage system comprising:

• a processing unit including a processor or a programmable logic device;
• a cache memory;
• and one or more storage devices and an interface to communicably connect with one or more storage devices;
• the method, executed by the processing unit, and comprising the steps of:
• managing metadata of operation management information for storing data to the one or more storage devices in units of blocks by configuring a tree of metadata for managing data, determining a capacity of the cache memory, based on the determined capacity of the cache memory, determining a tree level to be stored in the cache memory according to the determined capacity of the cache memory and an amount of metadata corresponding to the determined tree level, and storing the metadata of the tree up to the determined tree level, managing I/O access to data based on the metadata maintained in the cache memory and the metadata maintained in the one or more storage devices, accumulating updates of the metadata of the operation management information in the cache memory, and updating the metadata of the operation management information in the storage devices based on the metadata of the operation management information in the cache memory.