hesela.devSequential I/O
Sequential I/O is an access pattern in which successive requests in a stream address adjacent address ranges in order.
Address order: Small requests can be sequential; request size is a separate workload setting [1][2]. In a NAND SSD, host logical adjacency does not establish adjacent physical placement, because an FTL maps logical addresses to physical locations [3].
Benchmark setup: fio selects sequential reads or writes with rw=read or rw=write; blocksize and iodepth configure different dimensions. With multiple outstanding requests, completion order need not match submission order [2].
Relations
- related
- Random I/O, I/O request size, Queue depth, IOPS, Storage throughput, Solid-state drive (SSD), Hard disk drive (HDD), POSIX_FADV_SEQUENTIAL
Citations
- SNIA Dictionary, 28 April 2026: random I/O and sequential I/O, pp. 244-245 and 270.
- fio documentation: rw, blocksize, random_distribution, iodepth and serialize_overlap.
- Agrawal et al. Design Tradeoffs for SSD Performance. USENIX ATC 2008, section 3.1.
Sources & caveats
- The definitions are original paraphrases, not reproductions of SNIA Dictionary entries.
- The fio online manual was reviewed on 24 October 2026; option semantics describe a workload generator, not measured device performance.