Linux开机启动时间分析
👉 本文共约491个字，系统预计阅读时间或需2分钟。
简述
今天有同事咨询：项目上有台服务器操作系统启动时间较长，如何分析？
果然，好问题都来自实践。
经过查找，对于所有基于systemd的系统，可以使用systemd-analyze来分析系统启动时间。查看man手册，systemd-analyze blame和 systemd-analyze critical-chain可以有效分析
1 2 3 4 5 | systemd-analyze blame： This command prints a list of all running units, ordered by the time they took to initialize. This information may be used to optimize boot-up times. systemd-analyze critical-chain： This command prints a tree of the time-critical chain of units (for each of the specified UNITs or for the default target otherwise). The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. |
样例分析
服务器1
配置：四路X86服务器
操作系统：CentOS Linux release 8.5.2111
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | # systemd-analyze blame|head -n 15 50.902s unbound-anchor.service 21.032s mysql-monitor-agent.service 15.143s DmServiceDMSERVER.service 15.137s DmAPService.service 10.305s kdump.service 8.214s systemd-udev-settle.service 6.170s NetworkManager-wait-online.service 6.032s mysql-monitor-server.service 4.536s mysqld.service 2.194s dnf-makecache.service 2.117s tuned.service 1.328s dracut-initqueue.service 1.226s lvm2-monitor.service 813ms rdma-load-modules@rdma.service 672ms lvm2-pvscan@8:3.service # systemd-analyze critical-chain unbound-anchor.service The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. unbound-anchor.service +50.902s └─basic.target @9.108s └─sockets.target @9.108s └─spice-vdagentd.socket @9.108s └─sysinit.target @9.105s └─systemd-update-utmp.service @9.100s +5ms └─auditd.service @9.053s +45ms └─systemd-tmpfiles-setup.service @9.024s +24ms └─import-state.service @9.010s +13ms └─local-fs.target @9.009s └─boot.mount @8.956s +53ms └─systemd-fsck@dev-disk-by\x2duuid-e2c118b0\x2dc161\x2d4599\x2dacfe\x2dd574ba48cb64.service > └─local-fs-pre.target @8.923s └─lvm2-monitor.service @245ms +1.226s └─dm-event.socket @234ms └─-.mount └─system.slice └─-.slice |
服务器2
配置：四路X86服务器
操作系统：CentOS Linux release 7.9.2009 (Core)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | # systemd-analyze blame|head -n 15 1min 41.449s network.service 50.468s unbound-anchor.service 38.996s initial-setup.service 27.898s kdump.service 6.214s NetworkManager-wait-online.service 4.439s systemd-udev-settle.service 3.237s tuned.service 2.922s dev-mapper-centos\x2droot.device 1.715s lvm2-pvscan@8:3.service 1.112s containerd.service 1.005s docker.socket 1.004s lvm2-monitor.service 859ms dracut-initqueue.service 814ms postfix.service 756ms fwupd.service # systemd-analyze critical-chain network.service The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. network.service +1min 41.449s └─network-pre.target @7.418s |
服务器3
配置：2路 Phytium服务器
本人提供Oracle(OCP、OCM)、MySQL(OCP)、PostgreSQL(PGCA、PGCE、PGCM)等数据库的培训和考证业务，私聊QQ646634621或微信db_bao，谢谢！
操作系统：Kylin Linux Advanced Server release V10 (Sword)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | # systemd-analyze blame|head -n 15 19.884s NetworkManager-wait-online.service 14.006s rasdaemon.service 6.587s dracut-initqueue.service 3.324s kdump.service 2.607s plymouth-quit-wait.service 1.930s network.service 1.525s tuned.service 1.475s lvm2-monitor.service 995ms pmcd.service 791ms hdd.mount 637ms lvm2-pvscan@8:3.service 574ms initrd-switch-root.service 560ms systemd-sysctl.service 540ms dracut-pre-pivot.service 510ms udisks2.service # systemd-analyze critical-chain NetworkManager-wait-online.service The time when unit became active or started is printed after the "@" character. The time the unit took to start is printed after the "+" character. NetworkManager-wait-online.service +19.884s └─NetworkManager.service @4.107s +66ms └─network-pre.target @4.104s |
服务器4
配置：2路 鲲鹏服务器
操作系统：NFS Server release 3.1 (RTM4-A1)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | # systemd-analyze blame|head -n 15 47.635s systemd-fsck-root.service 26.005s NetworkManager-wait-online.service 8.968s plymouth-quit-wait.service 2.028s lvm2-pvscan@8:3.service 1.709s docker.service 1.650s fwupd.service 1.081s postfix.service 1.038s systemd-udev-settle.service 935ms lvm2-monitor.service 877ms dev-mapper-nfs\x2d\x2d3.1\x2droot.device 614ms tuned.service 590ms bolt.service 505ms rdma.service 496ms containerd.service 427ms network.service # systemd-analyze critical-chain systemd-fsck-root.service The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. systemd-fsck-root.service +47.635s └─systemd-readahead-replay.service @1.257s +39ms └─system.slice └─-.slice |
