Garbage Collection

Solid-state drives (SSDs) utilize NAND flash memory to store data, employing a process managed by the controller to ensure efficient storage and retrieval. Unlike traditional storage methods, SSDs cannot directly overwrite old data with new data. Instead, the existing data in the relevant block must first be erased before new data can be written. This process is facilitated through a mechanism known as Garbage Collection.

Key aspects of Garbage Collection include:

• Data Writing and Erasure Process:
  Data is written to the SSD in units called "pages," while data erasure occurs in larger units known as "blocks." When a block contains both valid and invalid data, the valid data must first be transferred to a new block to allow for the erasure of the invalid data.
• Reclaiming Storage Space:
  Once the valid data is migrated, the original block is completely erased, clearing all invalid data. This process creates a free block, making it available for subsequent data writing operations.
• Preserving Performance:
  By systematically managing data in this manner, Garbage Collection ensures that free blocks are consistently available, thereby maintaining the write performance and efficiency of the SSD.

This structured approach to data management is essential to sustaining the reliability and performance of SSDs over their operational lifespan.