We add an example limits.conf into the /etc/systemd/system/open-xchange.service.d directory with the following contents:

# Override and add options in this file
# See systemd.exec(5) for other limits

[Service]
#LimitNOFILE=16384

This way the admins can easily adjust limits like the maximum number of files.

To make the changes known to systemd the admin has to issue a 'systemctl daemon-reload' but systemd will inform the admin if he misses the reload before restarting the service to apply new limits.

The documentation for NRFILES in ox-scriptconf will be extended to point out the systemd peculiarity.

Furthermore we add the old default to our unit file open-xchange.service via
LimitNOFILE=8192 which was currently using a systemd default of 4096