If you need to create a large archive and want to spare your disk big IO operations then use the pv or cstream utility.

PV

Install the pv utility.

apt-get install pv

Create the archive with tar and pipe it to pv which will do the bandwidth throttling.

tar -cpzf - web/ | pv -L 1m > ./web.tar.gz

CSTREAM

Alternative way is to use cstream utility.

apt-get install cstream

Run command with bandwidth limit of 777k

tar cj file.txt | cstream -t 777k | tar xj -C /tmp/