Memory system for processing written data by zone and method of operating the same

A method of operating a memory system including a memory device and a memory controller, the method comprising:

• allocating, by the memory controller configured to control the memory device including a plurality of memory regions, some of the plurality of memory regions as allocated memory regions according to an allocation request of an external device;
• performing a write request of the external device in at least one of the allocated memory regions;
• detecting an error in a first memory region occurring from a data operation ordered by the write request,
• obtaining a value needed to close the first memory region based on a size of written data in the first memory region based on the write request;
• comparing the value to a first threshold based on a first reference value;
• maintaining the allocation of the first memory region in response to the value greater than or equal to the first threshold;
• and
• closing the first memory region in response to the value less than the first threshold.