系統無故重啟why

[yeung109]

# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 10.04.4 LTS
Release: 10.04
Codename: lucid

# last
reboot system boot 2.6.32-46-server Sun Feb 23 14:07 - 04:03 (13:56)

g# cat messages
Feb 23 06:25:47 test rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="718" x-info="http://www.rsyslog.com"] rsyslogd was HUPed, type 'lightweight'.
Feb 23 14:06:59 test kernel: Kernel logging (proc) stopped.
Feb 23 14:06:59 test rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="718" x-info="http://www.rsyslog.com"] exiting on signal 15.
Feb 23 14:07:26 test kernel: imklog 4.2.0, log source = /proc/kmsg started.
Feb 23 14:07:26 test rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="687" x-info="http://www.rsyslog.com"] (re)start
Feb 23 14:07:26 test rsyslogd: rsyslogd's groupid changed to 103
Feb 23 14:07:26 test rsyslogd: rsyslogd's userid changed to 101
Feb 23 14:07:26 test kernel: [ 0.000000] Initializing cgroup subsys cpuset
Feb 23 14:07:26 test kernel: [ 0.000000] Initializing cgroup subsys cpu
Feb 23 14:07:26test kernel: [ 0.000000] Linux version 2.6.32-46-server (buildd@lamiak) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1) ) #107-Ubuntu SMP Fri Mar 22 20:30:21 UTC 2013 (Ubuntu 2.6.32-46.107-server 2.6.32.60+drm33.26)