查看硬盘：
# fdisk -l
...
Disk /dev/sdb: 274.9 GB, 274877906944 bytes
255 heads, 63 sectors/track, 33418 cylinders, total 536870912 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdb doesn't contain a valid partition table
可以看到，有一块大小为256G的磁盘未初始化
格式化硬盘（如果需要多个分区，请先创建磁盘分区）：
# mkfs.ext4 /dev/sdb
mke2fs 1.42.9 (4-Feb-2014)
/dev/sdb is entire device, not just one partition!
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
16777216 inodes, 67108864 blocks
3355443 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
2048 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
查看磁盘的UUID：
# blkid
/dev/sda1: UUID="05003145-9b91-4943-aaa8-22cb496fd4d8" TYPE="ext4"
/dev/sda5: UUID="ca0012ba-2bf1-4d0b-94d3-3e4043746a14" TYPE="swap"
/dev/sdb: UUID="e23a1c1e-8d91-4df8-8fba-f0656a1080ab" TYPE="ext4"
记录下/dev/sdb（刚才格式化的分区）的UUID。
注意：你看到的UUID的值与例子不同
编辑/etc/fstab
# editor /etc/fstab
添加以下行
UUID=e23a1c1e-8d91-4df8-8fba-f0656a1080ab /home ext4 defaults,errors=remount-ro 0 1
注意：UUID替换为上一步你获取到的值
P.S./home为你要挂载的目标目录
现在重启电脑，应用新的磁盘配置
# reboot
查看磁盘配置：
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.8G 1.3G 7.1G 15% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 8.2G 4.0K 8.2G 1% /dev
tmpfs 1.7G 492K 1.7G 1% /run
none 5.0M 8.0K 5.0M 1% /run/lock
none 8.2G 0 8.2G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sdb 252G 60M 239G 1% /home
你好，我按照上面的操作，挂载到/home重启的话，会一直在登录界面，输密码。查询之后，说是 /home混乱引起的。tty1进入，把/etc/fstab 文件修改回原来的，重启就能进去。可能上面这样操作有点问题。
我之前的分配跟你差不多，全部都分在根目录。
现在发现有点小，加硬盘有问题。VM虚拟机上操作的。