We Ain't Afraid of No File Fragmentation: Causes and Prevention of Its Performance...
summary
Finds that fragmentation hurts SSD reads mainly through die-level collisions, not request splitting, because nonconsecutive die allocation from interleaved writes increases contention per die. Proposes an NVMe command extension plus a page-to-die allocation algorithm that uses two reserved bits (append/overwrite) and a 64-bit last-block address so contiguous logical blocks map to successive dies. Evaluations on commercial SSDs and an emulator show fixes for overwrites and fragmentation — worst-case drops cut from ~40% to 3.5% (162 MB SQLite) and typical cases drop to ~6%.
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