Linux shutdown restart five methods (SysRq shutdown halt init IPMI)

Linux shutdown restart five methods (sysrq shutdown halt init) Current version cat /etc/debian_version5.0.1 one, Linux shutdown command (top three types) 1, Shutdown -h now (-h:halt after shutdown.) haltinit 02, Linux Restart command shutdown -r (-r:reboot after shutdown.) Rebootinit 6 second, special case restart and shutdown (can ping   the above command can not be used in case   is the system hangs) 1, see if the kernel supports cat /boot/config-' uname  -r ' |grep  ' Config_magic_sysrq ' config_magic_sysrq=y2, temporarily on or off echo 0 > /proc/sys/ Kernel/sysrqecho 1 > /proc/sys/kernel/sysrq0 - disable sysrq completely1  - ENABLE ALL FUNCTIONS OF SYSRQ3, permanently set through the SYSCTL command SYSCTL -W KERNEL.SYSRQ =1sysctl -a|grep  "KERNEL.SYSRQ" kernel.sysrq = 14, specific command restart system echo  "B" > /proc/ Sysrq-trigger ' B '      - will immediately reboot the system  without syncing or unmounting         &nbsP;your disks. Shut down system  echo  "O" > /proc/sysrq-trigger ' o '      -  will shut your system off  (if configured and supported) .  three, Invoke IPMI command shutdown and restart (if configured) 1. Restart the machine ipmitool -ilanplus -h 172.16.1. -u root -p  123456 power reset2, power off ipmitool -i lanplus -h 172.16.1. -u root  -p 123456 power off some sysrq command parameters description ' B '       - Will  immediately reboot the system without syncing or unmounting your  Disks. ' C '       - will perform a system crash by a  null pointer dereference. A crashdump will be taken if configured. ' d '       - shows all locks that are held. ' E '     &nbsP; - send a sigterm to all processes, except for init. ' F '       - will call oom_kill to kill a memory  hog process. ' G '       - Used by kgdb  (Kernel debugger) ' H '        - Will display help  (actually any other key  than those listed here will display help. but  ' h '  is easy  to remember :-) ' i '       - send a sigkill to  all processes, except for init. ' J '       - Forcibly  "Just thaw it"  - filesystems  frozen by the fifreeze ioctl. ' K '       - Secure Access Key  (SAK)  KILLS ALL&NBsp;programs on the current virtual console. note: see important  Comments below in sak section. ' L '       - Shows a stack backtrace for all  Active cpus. ' M '       - Will dump current memory info to  Your console. ' n '       - used to make rt tasks nice-able ' o '        - Will shut your system off  (if configured  and supported). ' P '       - will dump the current registers and  flags to your console. ' Q '       - will dump per cpu lists of all  armed hrtimers  (but not regular timer_list timers) &nbsP;and detailed information about all clockevent devices. ' R '       - Turns off keyboard raw mode and  Sets it to xlate. ' S '       - Will attempt to sync all mounted  Filesystems. ' T '       - will dump a list of current tasks  and their information to your console. ' U '       - will attempt to remount all mounted  filesystems read-only. ' V '       - forcefully restores framebuffer console ' V '        - causes etm buffer dump [arm-specific] ' W '        - Dumps tasks that are in uninterruptable  (blocked)  stAte. ' X '       - used by xmon interface on ppc/powerpc  platforms. show global pmu registers on sparc64. ' Y '       - Show global CPU Registers [SPARC-64  Specific] ' Z '       - dump the ftrace buffer

This article is from the "7928217" blog, please be sure to keep this source http://7938217.blog.51cto.com/7928217/1643948

Linux shutdown restart five methods (SysRq shutdown halt init IPMI)