今早一臺服務器故障，後來有空上來查看故障日誌，未果，發現時間不對，如下：
[root@cache06 ~]# hwclock -w
Cannot access the Hardware Clock via any known method.
Use the --debug option to see the details of our search for an access method.
[root@cache06 ~]# hwclock --debug
hwclock from util-linux-2.13-pre7
hwclock: Open of /dev/rtc failed, errno=19: No such device.
No usable clock interface found.
Cannot access the Hardware Clock via any known method.
[root@cache06 ~]# ls -l /dev/rtc
rtc rtc0
通過查找資料發現是因爲升級內核是沒有加載相應的時間模塊導致，可用升級hwclock的方式解決，於是如下：
wget http://ftp.sjtu.edu.cn/sites/ftp.kernel.org/pub/linux/utils/util-linux-ng/v2.18/util-linux-ng-2.18.tar.gz
tar xzvf util-linux-ng-2.18.tar.gz
cd util-linux-ng-2.18
./configure
make
[root@cache06 util-linux-ng-2.18]# cd hwclock/
[root@cache06 hwclock]# ls
clock.h cmos.o hwclock.c kd.o Makefile.in rtc.o
clock-ppc.c hwclock hwclock.o Makefile README.hwclock
cmos.c hwclock.8 kd.c Makefile.am rtc.c
[root@cache06 hwclock]# ./hwclock
Mon 30 Jan 2012 04:52:54 PM CST -0.780277 seconds
[root@cache06 hwclock]# ./hwclock --show
Mon 30 Jan 2012 04:53:25 PM CST -0.333056 seconds
[root@cache06 hwclock]# date
Mon Jan 30 16:53:31 CST 2012
[root@cache06 util-linux-ng-2.18]#\cp hwclock/hwclock /sbin/