According to one embodiment, when receiving a write command including a first identifier of identifiers for accessing regions from a host, a memory system allocates one block of a common free block group shared by the regions as a write destination block for the region corresponding to the first identifier. When receiving a copy command including a block address of a copy source block of blocks belonging to the region corresponding to the first identifier, and an identifier of a copy destination target region indicative of the first identifier from the host, the memory system allocates one block as a copy destination block for the region corresponding to the first identifier, and copies data from the copy source block to the copy destination block.