Where is the rest of my sd card?

Question

I'm using a 4GB SD card, formatted with the debian image from a Windows PC. Here's the output of df -h:

Filesystem            Size  Used Avail Use% Mounted on
tmpfs                  94M     0   94M   0% /lib/init/rw
udev                   10M  156K  9.9M   2% /dev
tmpfs                  94M     0   94M   0% /dev/shm
rootfs                1.6G  1.5G     0 100% /
/dev/mmcblk0p1         75M   28M   47M  37% /boot

Where's all my extra space? About 2GB is missing!

Answer 1

It's there, but not set up as available space.

You can either use the remaining space as a separate drive/volume or resize the partition to the full 4gb

Answer 2

Because the image that you flashed to the Pi is only 2GB, that's all the space the root partition can see. Either you can resize the root partition or create a new one with fdisk.