Is there any system wide setting to enable asynchronous IO

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux
  • Asynchronous IO

Issue

  • Is there any system wide setting to enable async IO

Resolution

  • No, there is no option to enable async IO system wide. It has to be done from the application side and application must be capable of using async IO.

  • For instance Oracle can use both async and direct IO by setting the mount option filesystemio_options=setall and filesystemio_options=asynch to enable only async IO.

Root Cause

  • The AIO model is very different from the traditional UNIX model. It can't be used system wide unless application is aware on how to use this.

Diagnostic Steps

  • The following files can be used to monitor the use of async IO in the system:
    • /proc/sys/fs/aio-nr tells the number of active AIO transactions.
    • /proc/sys/fs/max-aio-nr tells the total number of concurrent IO AIO transactions that can take place system wide.

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