indicator-multiload

indicator-multiload is an indicator that gives you information about your CPU, Memory, Network, Swap, Load and disk.

You can install using the following command:

sudo apt-get install indicator-multiload

If the package if not found, you need to install the ppa repository:

sudo add-apt-repository ppa:indicator-multiload/stable-daily
sudo apt-get update
sudo apt-get install indicator-multiload