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原文排版地址 http://www.paraller.com/2015/10/22/%E9%98%BF%E9%87%8C%E4%BA%91Ecs%E6%8C%82%E8%BD%BD%E4%BA%91%E7%9B%98/

先购买一个云盘 500G大小

查看硬盘情况fdisk -l

查看是否有一个 /dev/xvdb 或者 数据盘大小与你要挂载一致的硬盘

Disk /dev/xvda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders, total 209715200 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: 0x000da36d

    Device Boot      Start         End      Blocks   Id  System
/dev/xvda1   *        2048   209713151   104855552   83  Linux

Disk /dev/xvdb: 214.7 GB, 214748364800 bytes            //重点
255 heads, 63 sectors/track, 26108 cylinders, total 419430400 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/xvdb doesn't contain a valid partition table

执行分区

fdisk /dev/xvdb ；对数据盘进行分区；根据提示，依次输入“n”，“p”“1”，两次回车，“wq”，分区就开始了，很快就会完成。

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x5c273d61.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-419430399, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-419430399, default 419430399):
Using default value 419430399

Command (m for help): wq
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

查看硬盘信息

fdisk -l 查看新的分区。新分区 xvdb1 已经创建好。如下面示例中的/dev/xvdb1

Disk /dev/xvda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders, total 209715200 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: 0x000da36d

    Device Boot      Start         End      Blocks   Id  System
/dev/xvda1   *        2048   209713151   104855552   83  Linux

Disk /dev/xvdb: 214.7 GB, 214748364800 bytes
86 heads, 25 sectors/track, 195083 cylinders, total 419430400 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: 0x5c273d61

    Device Boot      Start         End      Blocks   Id  System
/dev/xvdb1            2048   419430399   209714176   83  Linux

有两种情况，

• 你这个数据盘是新购买的，以前没有用过（没有存储过数据），那么就要对其进行格式化，使用 mkfs.ext3 /dev/xvdb1命令。
• 第二种，如果你之前就有数据盘，只是你把系统盘重置了，需要将数据盘再次挂载到重置后的系统上，那么就不要对其格式化（跳过此步骤），直接执行后面的步骤挂载就可以了。

mke2fs 1.42.9 (4-Feb-2014)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
13107200 inodes, 52428544 blocks
2621427 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
1600 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

挂载到 /mnt

前提是你已经创建了这个目录（创建目录的命令是mkdir）。以下命令写入新分区信息

echo '/dev/xvdb1  /mnt ext3    defaults    0  0' >> /etc/fstab

查看，出现以下信息就表示写入成功。

cat /etc/fstab

UUID=af414ad8-9936-46cd-b074-528854656fcd / ext4 errors=remount-ro 0 1
/dev/xvdb  /mnt ext3    defaults    0  0

挂载新分区

使用mount -a挂载，df -h命令查看，出现以下信息就说明挂载成功，可以开始使用新的分区了。

df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1       20G  1.3G   18G   7% /
none            4.0K     0  4.0K   0% /sys/fs/cgroup
udev            2.0G  4.0K  2.0G   1% /dev
tmpfs           396M  372K  395M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            2.0G     0  2.0G   0% /run/shm
none            100M     0  100M   0% /run/user
/dev/xvdb        99G   60M   94G   1% /mnt

常见问题

mount: /dev/xvdb is already mounted or /mnt busy

cat /etc/fstab 查看是否有重复的 ,重复的删除
umount -a
重新执行 mount -a