记一些基础的东西：
1、volume attach instance后，进入instance进行分区格式化，第二块盘名字为vdb：
[root@test ~]# fdisk -l
Disk /dev/vda: 53.7 GB, 53687091200 bytes, 104857600 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 label type: dos
Disk identifier: 0x000b2270
Device Boot Start End Blocks Id System
/dev/vda1 * 2048 104856254 52427103+ 83 Linux
Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 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
开始分区：
[root@test ~]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x7ecd0300.
Command (m for help): p
Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 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 label type: dos
Disk identifier: 0x7ecd0300
Device Boot Start End Blocks Id System
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 (2048-209715199, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199):
Using default value 209715199
Partition 1 of type Linux and of size 100 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
分区结束后，查看：
[root@test ~]# fdisk -l
Disk /dev/vda: 53.7 GB, 53687091200 bytes, 104857600 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 label type: dos
Disk identifier: 0x000b2270
Device Boot Start End Blocks Id System
/dev/vda1 * 2048 104856254 52427103+ 83 Linux
Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 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 label type: dos
Disk identifier: 0x7ecd0300
Device Boot Start End Blocks Id System
/dev/vdb1 2048 209715199 104856576 83 Linux
如果不格式化，直接去挂载，报错：
[root@test ~]# mount /dev/vdb1 /mnt
mount: /dev/vdb1 is write-protected, mounting read-only
mount: unknown filesystem type ‘(null)’
格式化：
[root@test ~]# mkfs.ext4 /dev/vdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
6553600 inodes, 26214144 blocks
1310707 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2174746624
800 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：
[root@test ~]# mount /dev/vdb1 /mnt
修改/etc/fstab:添加/dev/vdb1 /mnt ext4 defaults 0 0重启后自动挂载，永久生效
2、extend volume vdb后，重新attach：
[root@test ~]# fdisk -l
Disk /dev/vda: 53.7 GB, 53687091200 bytes, 104857600 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 label type: dos
Disk identifier: 0x000b2270
Device Boot Start End Blocks Id System
/dev/vda1 * 2048 104856254 52427103+ 83 Linux
Disk /dev/vdb: 128.8 GB, 128849018880 bytes, 251658240 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 label type: dos
Disk identifier: 0x7ecd0300
Device Boot Start End Blocks Id System
/dev/vdb1 2048 209715199 104856576 83 Linux
对vdb1进行扩容：
[root@test ~]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p
Disk /dev/vdb: 128.8 GB, 128849018880 bytes, 251658240 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 label type: dos
Disk identifier: 0x7ecd0300
Device Boot Start End Blocks Id System
/dev/vdb1 2048 209715199 104856576 83 Linux
Command (m for help): d
Selected partition 1
Partition 1 is deleted
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 (2048-251658239, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-251658239, default 251658239):
Using default value 251658239
Partition 1 of type Linux and of size 120 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
检查分区完整性：
[root@test ~]# e2fsck -f /dev/vdb1
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vdb1: 11/6553600 files (0.0% non-contiguous), 459544/26214144 blocks
分区扩容：
[root@test ~]# resize2fs /dev/vdb1
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vdb1 to 31457024 (4k) blocks.
The filesystem on /dev/vdb1 is now 31457024 blocks long.
挂载：
[root@test ~]# mount /dev/vdb1 /mnt
[root@test ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/vda1 50G 1.7G 49G 4% /
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 17M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
overlay 50G 1.7G 49G 4% /var/lib/docker/overlay/b00e0a4755ea2b6470c44ae489e832a08b836e933579f5b4e843626bb7386bda/merged
shm 64M 0 64M 0% /var/lib/docker/containers/8ab930a7c7cf1699b1e5b58ee7779fac54600ea3657411a7994fa6889042406a/shm
tmpfs 380M 0 380M 0% /run/user/0
/dev/vdb1 118G 60M 112G 1% /mnt