升级树莓派archlinux系统到新sd卡

由于之前把树莓派系统安装在4gb的sd卡上，随着系统的更新及安装了一大堆软件包之后，系统提示空间不足了。网上搜索了下，把所有数据迁移到新的sd卡上还是比较简单的。

克隆sd卡：

1，关闭树莓派电源，取出sd卡。插入到电脑的读卡器插槽中。

2，安装并运行Win32DiskImager。

3，在"Image File"选择框中，输入克隆的新文件路径。 例如，我放在"C:\Users\Yvan\Documents\archlinux.img"。

4， 在"Device"下拉框中，选择sd卡的盘符。

5，点击"Read"按钮，从sd卡中克隆新的镜像文件。

6，完成之后，插入新的sd卡，点击"Write"，把之前生成的镜像文件写入到新的sd卡中。

克隆完之后，需要扩展分区。

步骤如下：

1. After logging in you view the status of filesystem:

[root@alarmpi ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       1.7G  444M  1.2G  28% /
devtmpfs         83M     0   83M   0% /dev
tmpfs           231M     0  231M   0% /dev/shm
tmpfs           231M  236K  231M   1% /run
tmpfs           231M     0  231M   0% /sys/fs/cgroup
tmpfs           231M     0  231M   0% /tmp
/dev/mmcblk0p1   90M   24M   67M  27% /boot

2. Using the command fdisk will edit the filesystem /dev/mmcblk0:

[root@alarmpi ~]# fdisk /dev/mmcblk0
Welcome to fdisk (util-linux 2.23.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
 
Command (m for help):

3. List the information and delete partition 2

Command (m for help): p
 
Disk /dev/mmcblk0: 7969 MB, 7969177600 bytes, 15564800 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: 0x00057540
 
        Device Boot      Start         End      Blocks   Id  System
/dev/mmcblk0p1            2048      186367       92160    c  W95 FAT32 (LBA)
/dev/mmcblk0p2          186368     3667967     1740800    5  Extended
/dev/mmcblk0p5          188416     3667967     1739776   83  Linux
 
Command (m for help): d
Partition number (1,2,5, default 5): 2
Partition 2 is deleted
 
Command (m for help):

4. Create a new extended partition a logical volume

Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p): e
Partition number (2-4, default 2): 2
First sector (186368-15564799, default 186368):
Using default value 186368
Last sector, +sectors or +size{K,M,G} (186368-15564799, default 15564799):
Using default value 15564799
Partition 2 of type Extended and of size 7.3 GiB is set
 
Command (m for help): n
Partition type:
   p   primary (1 primary, 1 extended, 2 free)
   l   logical (numbered from 5)
Select (default p): l
Adding logical partition 5
First sector (188416-15564799, default 188416):
Using default value 188416
Last sector, +sectors or +size{K,M,G} (188416-15564799, default 15564799):
Using default value 15564799
Partition 5 of type Linux and of size 7.3 GiB is set
 
Command (m for help):

5. !! Check whether top block starts in the same place as the original (start)

Command (m for help): p
 
Disk /dev/mmcblk0: 7969 MB, 7969177600 bytes, 15564800 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: 0x00057540
 
        Device Boot      Start         End      Blocks   Id  System
/dev/mmcblk0p1            2048      186367       92160    c  W95 FAT32 (LBA)
/dev/mmcblk0p2          186368    15564799     7689216    5  Extended
/dev/mmcblk0p5          188416    15564799     7688192   83  Linux
 
Command (m for help):

6. If it starts again (in this case on 186368 p2 a 188416 p5) write changes and reboot.

Command (m for help): w
The partition table has been altered!
 
Calling ioctl() to re-read partition table.
 
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@alarmpi ~]# reboot

7. After booting the system we online enlarge root partitions

[root@alarmpi ~]# resize2fs /dev/mmcblk0p5
resize2fs 1.42.8 (20-Jun-2013)
Filesystem at /dev/mmcblk0p5 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mmcblk0p5 is now 1922048 blocks long.

8. Check and it is done :-)

[root@alarmpi ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       7.3G  447M  6.5G   7% /
devtmpfs         83M     0   83M   0% /dev
tmpfs           231M     0  231M   0% /dev/shm
tmpfs           231M  236K  231M   1% /run
tmpfs           231M     0  231M   0% /sys/fs/cgroup
tmpfs           231M     0  231M   0% /tmp
/dev/mmcblk0p1   90M   24M   67M  27% /boot

参考：http://lifehacker.com/how-to-clone-your-raspberry-pi-sd-card-for-super-easy-r-1261113524
http://raspberry-hosting.com/faq/how-expand-arch-linux-root-partition
http://elinux.org/RPi_Easy_SD_Card_Setup#Manually_resizing_the_SD_card_on_Raspberry_Pi