noop
also: noop scheduler, no-op elevator
A scheduling elevator algorithm that performs no optimization, processing I/O requests in the exact order they arrive without reordering or merging.
The noop (no operation) scheduler is an I/O elevator algorithm in the Linux kernel that queues disk requests in a simple FIFO (first-in-first-out) manner. Unlike more complex schedulers, it performs minimal reordering and merging of requests, making it ideal for systems where the underlying hardware or storage device (like an SSD) already handles its own optimization.
The noop scheduler can actually improve performance on certain storage devices by reducing scheduler overhead and allowing the device firmware to make better decisions about request ordering. For example, on solid-state drives where seek time is negligible, the noop scheduler often outperforms more aggressive schedulers like CFQ (Completely Fair Queueing) that were designed for rotational hard drives.
You can view the current I/O scheduler and switch to noop by writing to /sys/block/sdX/queue/scheduler, where X is your device identifier. For instance: echo noop > /sys/block/sda/queue/scheduler