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