core_dump_analysis.md

修改core dump存储位置

/proc/sys/kernel/core_pattern 设置了生成core文件的路径，参考 man core

echo '/tmp/core_%e.%p' | sudo tee /proc/sys/kernel/core_pattern

上述命令可以使得core文件保存在/tmp目录下的 core_[program].[pid]

设置sysrq和nmi

• 启用sysrq

echo 1 | sudo tee /proc/sys/kernel/unknown_nmi_panic

• 启用nmi

echo 1 | sudo tee /proc/sys/kernel/sysrq

• 触发crash

echo c | sudo tee /proc/sysrq-trigger

• 也可以通过ipmi再次发送nmi（终极大招）

ipmitool -I lanplus -H <OOB_IP> -U <USERNAME> -P <PASSWORD> chassis power diag

排查XEN服务器hang机core dump的一个实战案例

参考

• Changing location of core dump
• Generating an NMI through IPMI
• [How to trigger SysRq from ipmitool and ipmiconsole using the SysRq magic keys over an HP iLO4 ?](How to trigger SysRq from ipmitool and ipmiconsole using the SysRq magic keys over an HP iLO4 ?)
• How to do SOL (Serial Over LAN aka Console Redirection) on Dell Servers