linux – 无法挂载磁盘(VFS：找不到ext4文件系统)

#mount -t ext4 /dev/sda /data

mount: wrong fs type,bad option,bad superblock on /dev/sda,missing codepage or helper program,or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

#dmesg | tail -1
       EXT4-fs (sda): VFS: Can't find ext4 filesystem

我究竟做错了什么？
我看到许多有类似问题的海报都要求发布fstab的内容,所以这里是：

#cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Wed Aug  6 11:29:15 2014
#
# Accessible filesystems,by reference,are maintained under '/dev/disk'
# See man pages fstab(5),findfs(8),mount(8) and/or blkid(8) for more info
#
UUID=276c97cc-9c5f-496f-a56f-ac3a45c58a26           /           ext4    defaults,usrquota,grpquota  1 1
UUID=3978f122-03d4-48db-adeb-6fc8a2c624c4 /boot                   ext2    defaults        1 2
UUID=1251c6d8-c417-48df-9cf4-2f56e3a823a6 /tmp                    ext4    defaults        1 2
UUID=95fd67df-7172-4ac9-9264-0b50819a203a swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0

CentOs 6

更新：

# cat /proc/partitions 
major minor  #blocks  name

   8       32  244198584 sdc
   8       33     102400 sdc1
   8       34    4194304 sdc2
   8       35    2097152 sdc3
   8       36          1 sdc4
   8       37  237802496 sdc5
   8       48  244198584 sdd
   8       49     102400 sdd1
   8       50    4194304 sdd2
   8       51    2097152 sdd3
   8       52          1 sdd4
   8       53  237802496 sdd5
   8        0 21484255232 sda
   8       16 21484255232 sdb
   9        1    4192192 md1
   9        3  237671232 md3
   9        2    2096064 md2
   9        0     102336 md0

#fdisk -l | grep sda
Disk /dev/sda: 21999.9 GB,21999877357568 bytes