In another question I was concerned about the iSCSI service taking precious boot time away, while I did not need this service at all.
I have also found that to improve boot time I could use
returns a list of various services launched at boot and the time it took to launch them and do their thing in milliseconds.
systemd-analyze plot > plot.svg
creates a graphic plot of the latest boot in SVG format.
systemctl stop SERVICENAME.serviceand
systemctl disable SERVICENAME.service
stop a running service and disable it at boot respectively.
etc. more on this post.
Now I removed some services based on the suggestion of more experienced and knowledgeable users. My boot dramatically was shortened by almost 60 % (from 62s to 26s!). Some of the services I removed were:
It is also suggested I should remove:
It seems that much services are running while I do not need them. On the other hand I have hardly any information about those services. Some are obvious in their use like the sendmail.service, others are more obscure like the fedora-wait-storage.service.
If I now run
systemd-analyze blame it returns a list of services launched at boot. How can I find out what service does what? Is there a way to query these services about their identity and activity? Is there documentation? How to determine what service I need and which one I don't?
11885ms fedora-storage-init.service 4966ms fedora-loadmodules.service 3499ms systemd-vconsole-setup.service 2744ms fedora-readonly.service 2574ms remount-rootfs.service 2436ms media.mount 2416ms sys-kernel-debug.mount 2405ms dev-hugepages.mount 2397ms sys-kernel-security.mount 2387ms dev-mqueue.mount 1934ms udev-trigger.service 1807ms netfs.service 1679ms mdmonitor-takeover.service 1622ms fcoe.service 1608ms udev.service 1493ms systemd-remount-api-vfs.service 784ms sys-kernel-config.mount 503ms fedora-storage-init-late.service 492ms NetworkManager.service 490ms systemd-sysctl.service 410ms lvm2-monitor.service 389ms avahi-daemon.service 337ms console-kit-log-system-start.service 291ms rsyslog.service 256ms systemd-logind.service 239ms livesys.service 233ms ip6tables.service 230ms iptables.service 216ms systemd-readahead-replay.service 213ms auditd.service 211ms boot.mount 207ms systemd-readahead-collect.service 199ms sshd-keygen.service 176ms irqbalance.service 147ms abrt-vmcore.service 146ms systemd-tmpfiles-setup.service 134ms mcelog.service 122ms abrt-ccpp.service 114ms dbus.service 79ms console-kit-daemon.service 60ms sandbox.service 37ms home.mount 30ms livesys-late.service 12ms systemd-user-sessions.service 7ms rtkit-daemon.service 7ms accounts-daemon.service 0ms sys-fs-fuse-connections.mount