I have a new CentOS 7 installation, and noticed that my /var/log/messages file is full of messages like thisMar  6 08:40:01 myhostname systemd: Started Session 2043 of user root.Mar  6 08:40:01 myhostname systemd: Starting Session 2043 of user root.Mar  6 08:40:01 myhostname systemd: Created slice user-1001.slice.Mar  6 08:40:01 myhostname systemd: Starting user-1001.slice.Mar  6 08:40:01 myhostname systemd: Started Session 2042 of user userx.Mar  6 08:40:01 myhostname systemd: Starting Session 2042 of user userx.Mar  6 08:40:01 myhostname systemd: Started Session 2041 of user root.Mar  6 08:40:01 myhostname systemd: Starting Session 2041 of user root.Mar  6 08:40:31 myhostname systemd: Removed slice user-1001.slice.Mar  6 08:40:31 myhostname systemd: Stopping user-1001.slice.Mar  6 08:41:01 myhostname systemd: Created slice user-1001.slice.Mar  6 08:41:01 myhostname systemd: Starting user-1001.slice.Mar  6 08:41:01 myhostname systemd: Started Session 2044 of user userx.Mar  6 08:41:01 myhostname systemd: Starting Session 2044 of user userx.Mar  6 08:41:21 myhostname systemd: Removed slice user-1001.slice.Mar  6 08:41:21 myhostname systemd: Stopping user-1001.slice.What do all of these mean, and why are they there?  If this is normal background noise them it seems like an enourmous waste to of resources to log this...
System log full of session and slice messages
syslog
(this question is also answered over on superuser here )Those are messages pertaining to the creation and deletion of slices, which are used in systemd to group processes and manage their resources. Why they are logged by default escapes me but I've seen two ways to disable them:The less intrusive way is to filter them out by creating /etc/rsyslog.d/ignore-systemd-session-slice.conf with the following contents:if $programname == systemd and ($msg contains Starting Session or $msg contains Started Session or $msg contains Created slice or $msg contains Starting user- or $msg contains Removed Slice or $msg contains Stopping user-) then stopand restart rsyslogd with systemctl restart rsyslogThe broader way is to set the systemd logging level a bit higher by editing /etc/systemd/system.conf: #LogLevel=info LogLevel=noticeReferences:https://access.redhat.com/solutions/1564823I have more but can't post more than 2 links. Hooray.