aio - Linux


aio is a Linux command for performing asynchronous input and output (IO) operations. It allows programs to initiate IO operations and continue with other tasks while the IO is being performed in the background. This can significantly improve the performance of applications that require a lot of IO operations.


aio [-h] [-v] [-d] [-s DELAY] [-n NUM_OPS] [-b BLOCK_SIZE] [-f FILENAME] [-o OUTPUT_FILE]


  • -h: Display help and usage information.
  • -v: Enable verbose mode to display additional information about the IO operations.
  • -d: Enable debugging mode to display even more detailed information about the IO operations.
  • -s DELAY: Specify the delay (in milliseconds) between each IO operation. Defaults to 100.
  • -n NUM_OPS: Specify the number of IO operations to perform. Defaults to 1000.
  • -b BLOCK_SIZE: Specify the size (in bytes) of each IO operation. Defaults to 1024.
  • -f FILENAME: Specify the file to perform IO operations on.
  • -o OUTPUT_FILE: Specify the file to write the results of the IO operations to.


Simple usage

Perform 100 asynchronous IO operations on a file named myfile.txt:

aio -f myfile.txt

Complex usage

Perform 1000 asynchronous IO operations on a file named myfile.txt, each operation being 4096 bytes in size, with a delay of 500 milliseconds between each operation:

aio -f myfile.txt -n 1000 -b 4096 -s 500

Common Issues

  • Permission denied: Ensure that the user has the necessary permissions to access the specified file.
  • File not found: Verify that the specified file exists and is accessible.
  • Invalid arguments: Check that the specified arguments are valid and within the allowed ranges.


aio can be integrated with other Linux commands and tools to create powerful scripts and pipelines. For example, aio can be used to:

  • Generate test data: Create a large number of files or records for testing purposes.
  • Benchmark IO performance: Measure the speed of different storage devices or file systems.
  • Monitor IO activity: Track the number and size of IO operations on a system.

Related Commands

  • dd: Copy or convert data between files.
  • hd: Display the contents of a file in hexadecimal and ASCII formats.
  • iotop: Monitor disk IO usage.