Method of operating memory system and memory system performing the same

A method of operating a memory device, the method comprising:

• determining a first garbage collection (GC) level among a plurality of GC levels based on a level of decrease of free blocks among a plurality of memory blocks;
• adjusting a size of a data sample associated with executions of host input/output requests and GC input/output requests to generate the data sample having the adjusted size, based on the first GC level;
• and
• performing the host input/output requests and the GC input/output request, based on the data sample.

A method of operating a memory controller, the method comprising:

• detecting a level of decrease of free blocks among a plurality of memory blocks;
• determining a first garbage collection (GC) level among a plurality of GC levels, based on the level of decrease;
• adjusting a data sample associated with executions of host input/output requests and GC input/output requests to generate the data samples having the adjusted size, based on the first GC level;
• and
• issuing the host input/output requests and the GC input/output request to a memory device, based on the data sample.