Много лишних записей в логе следующего вида в Centos 7
tail messages
Jan 26 22:01:01 kvm systemd: Started Session 905 of user root.
Jan 26 22:01:01 kvm systemd: Starting Session 905 of user root.
Jan 26 22:01:01 kvm systemd: Removed slice user-0.slice.
Jan 26 22:01:01 kvm systemd: Stopping user-0.slice.
Jan 26 22:37:48 kvm systemd: Created slice user-0.slice.
Jan 26 22:37:48 kvm systemd: Starting user-0.slice.
Jan 26 22:37:48 kvm systemd: Started Session 906 of user root.
Jan 26 22:37:48 kvm systemd: Starting Session 906 of user root.
Jan 26 22:37:48 kvm systemd-logind: New session 906 of user root.
Отключить можно
systemd-analyze set-log-level notice