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