How do I set the size of /run

I’m running AlmaLinux 9.2 on a small embedded(-ish) system, where I like to keep a lot of stuff in /run. When I was using CentOS7.x this was on the order of 1.5G, and I never really thought about it. However, since we have moved to Alma9, the default size of /run is only ~720M on the same hardware.

I can set the size by adding a line in /etc/fstab - but that seems a bit old-fashioned these days. For the /run/user/<uid> I can set a parameter RuntimeDirectorySize in /etc/systemd/logind.conf, but I haven’t found anything similar for the entire /run.

Surely there must be a systemd-specific way of specifying this?

It looks like there is indeed no systemd-native way to do this. Instead, the systemd documentation explicitly says:

Even though normally none of these API file systems are listed in /etc/fstab they may be added there. If so, any options specified therein will be applied to that specific API file system. Hence: to alter the mount options or other parameters of these file systems, simply add them to /etc/fstab with the appropriate settings and you are done.

(The keyword here is API file system - which apparently includes all the non-disk-based filesystems, such as /dev/, /sys etc.