Well, I think the problem with the swap in this instance would have been due to not being enough of it. You said the VM has 2GB ram, with 1.1GB of it in use. Assuming that was a single process running with 1.1GB, when dnf was running and required ram, it would have wanted to move (at that time) unused processes to swap. If swap is only 1GB, it won’t be able to put the 1.1GB process into it, and so that would fail. In this case, the system should OOM kill the largest process. Theoretically that should have been the 1.1GB process, since dnf at that point only had available 900MB ram (2GB - 1.1GB).
Ideally swap should be double ram for this instance, so 4GB. There is a point when you get over a certain amount of ram, that you start decreasing the size of the swap. But, that all depends on what you are doing with your system. For example, with my laptop, I still need double the ram size for it to suspend/hibernate properly.
This link by RH: Chapter 15. Swap Space | Red Hat Product Documentation
shows, 2-8GB should have the swap equal to the amount of ram. I would however even at this level still have double the ram. Once I get to 16GB ram, I would only then think about having the swap the same as the amount of ram.
You can also set vm.swappiness and change ot from the default of 60 to a lower value to prefer using ram over swap. Eg:
echo 0 > /proc/sys/vm/swappiness
or by setting in /etc/sysctl.d/99-local.conf or whatever filename you want:
vm.swappiness = 0
all that will say is prefer using ram, but only use swap if necessary. Most databases will say to set this to zero. I’ve seen this for Java apps as well. I used to set it to 10 for the majority of my systems, but now I just set it to zero. Setting to zero doesn’t mean it won’t use swap, it will still do it but only if necessary.