/var/log/目录已满：
[root@bogon ~]# du -hs /var/log/*
4.0K /var/log/aide
4.0K /var/log/amanda
......
1.1G /var/log/messages
308K /var/log/messages-20120315
416K /var/log/messages-20120318
......
清空messages文件：
[root@bogon ~]# echo >/var/log/messages