Clear Linux uses /usr/lib/systemd/system.conf.d/50-nfiles.conf to
configure the maximum number of open file descriptors.
Copy this file to /etc/systemd/system.conf.d and modify the value.
sudo mkdir -p /etc/systemd/system.conf.d
sudo cp /usr/lib/systemd/system.conf.d/50-nfiles.conf /etc/systemd/system.conf.d
sudo nano /etc/systemd/system.conf.d/50-nfiles.conf
Use your favorite editor 