系统重启问题

我设置了系统每天固定重启，但有时候，系统关掉了，却没有再起来，请问，这会是什么原因
大概日志：
Dec 17 04:00:01 linux25 shutdown: shutting down for system reboot
Dec 17 04:00:05 linux25 init: Switching to runlevel: 6
Dec 17 04:00:06 linux25 atd: atd shutdown succeeded
Dec 17 04:00:07 linux25 rc: Stopping keytable:  succeeded
Dec 17 04:00:07 linux25 gpm: gpm shutdown succeeded
Dec 17 04:00:07 linux25 sshd: sshd -TERM succeeded
Dec 17 04:00:08 linux25 pop-before-smtp: pop-before-smtp shutdown succeeded
Dec 17 04:00:08 linux25 vsftpd: vsftpd shutdown succeeded
Dec 17 04:00:09 linux25 xinetd[3714]: Exiting...
Dec 17 04:00:09 linux25 xinetd: xinetd shutdown succeeded
Dec 17 04:00:09 linux25 crond: crond shutdown succeeded
Dec 17 04:00:09 linux25 dd: 1+0 records in
Dec 17 04:00:09 linux25 dd: 1+0 records out
Dec 17 04:00:09 linux25 random: Saving random seed:  succeeded
Dec 17 04:00:09 linux25 kernel: Kernel logging (proc) stopped.
Dec 17 04:00:09 linux25 kernel: Kernel log daemon terminating.
Dec 17 04:00:10 linux25 syslog: klogd shutdown succeeded
Dec 17 04:00:10 linux25 exiting on signal 15
在这个之后，日志就停了

不太懂

我说得不明白吗