minimum-io-size · shipping · also minimum_io_size, MIN-IO, io_min

Minimum I/O size

Minimum I/O size is a Linux block-layer hint for the preferred smallest request granularity, not the smallest addressable unit.

The value is in bytes. Linux raises io_min to at least physical_block_size during queue-limit validation, so equality can reflect a default rather than a measured optimum. [2]

Relations

related

Optimal I/O size, Alignment offset, Logical sector, Physical sector, Partition alignment, Direct-I/O alignment

Advantages

• The read-only blockdev --getiomin query exposes the value for a selected block-device path. [3]

Limitations

• A performance hint does not replace logical-sector or direct-I/O validity checks. [1]

Citations

1. Linux 6.12: stable sysfs block ABI, sector sizes and I/O topology (accessed 2026-10-19)
2. Linux 6.12: block limits validation and bdev_alignment_offset (accessed 2026-10-19)
3. util-linux 2.40.2: blockdev query options and byte units (accessed 2026-10-19)

Further reading

4. Hesela: 512e, 4Kn and alignment: geometry is not durability (accessed 2026-10-19)

JSON: /data/terms/minimum-io-size.json