Resize the root partition to fill the SD card or Nand
From wiki
A very common problem when installing an image, is only having a very small amount of usable space. In this tutorial I will show you how to re-size the partition to encompass your whole SD Card.
use image flashed onto marsboard was only 2GB and only see 2GB of storage space on the disk.
You can now verify that the system is using 2G of the SD Card or Nand by entering the following command:
df -h
for example, enter the following command:
sudo resize2fs /dev/mmcblk0
You can now verify that the system is using the full capacity of the SD Card by entering the following command:
df -h
