---
tags:
  - sysctl
  - aio
  - linux
  - filesystem
references:
  - https://docs.kernel.org/admin-guide/sysctl/fs.html
  - https://man7.org/linux/man-pages/man2/io_setup.2.html
  - https://sort.veritas.com/public/documents/HSO/2.0/linux/productguides/html/hfo_admin_ubuntu/ch04s03.htm
---
aio-nr & aio-max-nr:

```
aio-nr is the running total of the number of events specified on the
io_setup system call for all currently active aio contexts.  If aio-nr
reaches aio-max-nr then io_setup will fail with EAGAIN.  Note that
raising aio-max-nr does not result in the pre-allocation or re-sizing
of any kernel data structures.
```

Openstack compute fs.aio-max-nr naar `1048576` gezet zoals beschreven op het web.