Backup File Size

Update 12 July 2012

For quite a while now I have been keeping track of the growing size of my backup file.  I keep all my files and working data on a 250GB USB drive and back this up on my Mac system as a backup tar file.  Since tar is not a compressed format, the size of this file represents essentially how much digital information I am generating and accumulating.  The plot below shows how this has grown over time.

In the linear regression equation, y is backup file size in GB and x is time in years since 5/19/2008 (when I started keeping track).  The file size is doubling about every 2 years.  It won't be long before my 250GB drive will have to be retired.