kernel: [829455.595333][ C10] critical target error, dev sda, sector 104056241 op 0x3:(DISCARD) ......如果是在 VMware 上运行的虚拟机在日志里出现 critical target error 此类报错，尤其是涉及到 DISCARD 操作的错误，通常是由 VMware 进行硬盘垃圾空间回收或者进行硬盘优化造成的。
VMware 的控制平台上，检查宿主机的硬盘是否正常。若不正常则修复或者更换硬盘。
This Linux server is a virtual server. If we reboot it though its virtual software, there is no relevant logs in the /var/log/messages.
This Linux server is a member of a pacemaker cluster. If the pacemaker cluster software fences this server for protecting the whole cluster, there is no relate logs in the /var/log/messages.
This Linux server has critical problems in its system or hardware. Core panic of Linux and hardware problem both can reboot the system automatically without any reboot logs in the /var/log/messages.
# /etc/init.d/vmware start
# vmplayer在 VMware 的官网上下载软件 VMware Workstation Player（本次使用的是 VMware-Player-15.5.6-16341506.x86_64.bundle）：
服务器系统要配置好可用的软件源
# yum -y install perl gcc kernel-devel libX11 libXinerama libXcursor libXtst elfutils-libelf-devel# chmod u+x VMware-Player-15.5.6-16341506.x86_64.bundle（补充：本次添加权限的是 VMware-Player-15.5.6-16341506.x86_64.bundle）
# ./VMware-Player-15.5.6-16341506.x86_64.bundle（补充：本次安装的是 VMware-Player-15.5.6-16341506.x86_64.bundle）