/Somehow it seems as if I'm receiving messages from the mailing list -
but mine do not seem to get through. So I'm trying again./

Hi,

currently I started testing fairly fast NVMe-drives and I for the first
time I dealt with the question whether the io engine is sufficient (up
till now I just the default /libaio/). I found some information on
io_uring online and now tried to switch to that engine:

fio --bs=1M --rw=randwrite --numjobs=1 --iodepth=1  --size=10000M
--filename=/dev/nvme0n1 --name=mylittletest --direct=1 --fsync=1 
--refill_buffers --ioengine=io_uring --group_reporting --fallocate=none
--runtime=60 --time_based --hipri

But it crashes with the following information: fio: pid=2490,
err=38/file:engines/io_uring.c:699, func=io_queue_init, error=Function
not implemented

My system:

 1. fio-3.25
 2. CentOS8 (Kernel 4.18.0-240.1.1.el8_3.x86_64)
 3. I have installed the packes liburing and liburing-devel

Am I doing something wrong?

Kind regards
Daniel