Delayed TRIM for Reducing Trim Overhead

We propose Delayed TRIM to mitigate the overhead associated with TRIM requests. While conventional TRIM reduces unnecessary data copying in GC by instantly notifying the device of deleted data, it incurs considerable overhead. In contrast, Delayed TRIM executes only the essential steps immediately and defers the remaining actions until the device is idle. A trim buffer and trim validity bitmap are employed to ensure data integrity during this delay. Experiments with DaisyPlus OpenSSD demonstrate that this technique maintains the WAF while effectively reducing TRIM overhead.