Do your sleep processes show up in the output of "systemctl status ssh.service" in the CGroup section? For me they do (sample with just one process backgrounded):
# systemctl status ssh.service ● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled) Active: active (running) since Fri 2016-04-01 05:53:59 UTC; 1min 1s ago Main PID: 2928 (sshd) Tasks: 10 (limit: 512) CGroup: /system.slice/ssh.service ├─2928 /usr/sbin/sshd -D ├─4966 sshd: jrosenboom [priv ├─5087 sshd: jrosenboom@pts/ ├─5127 -bash ├─5208 sudo -i ├─5213 sudo -i ├─5214 -bash ├─6386 sleep 100 ├─6403 systemctl status ssh.service └─6404 pager -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to openssh in Ubuntu. https://bugs.launchpad.net/bugs/1564451 Title: User processes are counted towards systemd limit for sshd processes To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/1564451/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs