今早一台服务器故障，后来有空上来查看故障日志，未果，发现时间不对，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 

通过查找资料发现是因为升级内核是没有加载相应的时间模块导致，可用升级hwclock的方式解决，于是如下：

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/