树莓派3安装Centos 7后的SD扩容

好长时间没有鼓动树莓派了，前段时间出点的小问题SD卡坏掉了，昨天新的SD卡回来，重新烧入Centos 7，但是发现我的可用空间只有2G,这怎么够用呢！

下面是我自己的执行记录，整个执行过后，我的SD空间就整个都打开了。

Last failed login: Sat Nov 18 04:09:01 UTC 2017 from 192.168.31.119 on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Sat Nov 18 04:01:16 2017 from 192.168.31.119
[root@centos-rpi3 ~]# ls
README
[root@centos-rpi3 ~]# cat README
== CentOS 7 userland ==

If you want to automatically resize your / partition, just type the following (as root user):
/usr/bin/rootfs-expand


[root@centos-rpi3 ~]# sudo /usr/bin/rootfs-expand
Extending partition 3 to max size ....
CHANGED: partition=3 start=2074624 old: size=4194304 end=6268928 new: size=120068063,end=122142687
Resizing ext4 filesystem ...
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/mmcblk0p3 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 8


The filesystem on /dev/mmcblk0p3 is now 15008507 blocks long.

Done.
[root@centos-rpi3 ~]#

[root@centos-rpi3 ~]# df -lh
文件系统        容量  已用  可用 已用% 挂载点
/dev/root        57G  873M   54G    2% /
devtmpfs        460M     0  460M    0% /dev
tmpfs           464M     0  464M    0% /dev/shm
tmpfs           464M   12M  452M    3% /run
tmpfs           464M     0  464M    0% /sys/fs/cgroup
/dev/mmcblk0p1  500M   50M  451M   10% /boot
tmpfs            93M     0   93M    0% /run/user/0
[root@centos-rpi3 ~]#