最近三个月，阿里云上的mysql经常性自动停机，查看mysql运行日志：
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# tail -n 20 /var/log/mysqld.log 160122 8:59:12 InnoDB: Completed initialization of buffer pool 160122 8:59:12 InnoDB: Started; log sequence number 0 2303872052 160122 8:59:12 [Note] Event Scheduler: Loaded 0 events 160122 8:59:12 [Note] /usr/libexec/mysqld: ready for connections. Version: '5.1.73' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution 160127 1:20:27 [Note] /usr/libexec/mysqld: Normal shutdown 160127 1:20:27 [Note] Event Scheduler: Purging the queue. 0 events 160127 1:20:29 InnoDB: Starting shutdown... 160127 1:20:31 InnoDB: Shutdown completed; log sequence number 0 2310021287 160127 1:20:31 [Note] /usr/libexec/mysqld: Shutdown complete 160127 01:20:31 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended |
google问题：http://serverfault.com/questions/499052/mysql-instance-on-centos-6-4-suddenly-stopped
网友提示查看系统日志：
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# cat /var/log/messages Jan 27 01:20:11 AY0000000000000000000Z kernel: Clocksource tsc unstable (delta = 4686958600 ns). Enable clocksource failover by adding clocksource_failover kernel parameter. |
系统日志时钟源报错，默认时钟源tsc不稳定
查看当前系统可用时钟源和正在采用的时钟源，我的主机环境是阿里云xen虚拟主机CentOs 6.3发行版：
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# cat /sys/devices/system/clocksource/clocksource0/available_clocksource tsc acpi_pm # cat /sys/devices/system/clocksource/clocksource0/current_clocksource tsc |
How to fix Clocksource tsc unstable
根据上文网友提供解决方案，我修改了grub.conf文件，内核配置段添加了故障切换时钟源acpi_pm。
不过，机器重启之后，检测的时钟源仍然是tsc，不知道，这样算是成功了吗？
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notsc clocksource=acpi_pm |
到grub.conf文件内核配置指令结尾，重启机器。OK
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# cat /sys/devices/system/clocksource/clocksource0/available_clocksource acpi_pm # cat /sys/devices/system/clocksource/clocksource0/current_clocksource acpi_pm |
怀疑某次的oracle rac宕机和Clocksource tsc unstable有关系。节点2报了，节点1正常。
