The small hole in this picture is being reported as the cause of the ISS leak. What is the large hole next to it on the perpendicular surface? The one that appears to have been drilled by an amatuer with a hole saw? Does it have a purpose?
It's a lightening hole.
The structure you see on the upper right of the image is a ring frame with a flanged C-channel cross-section that goes around the circumference of the Soyuz orbital module pressure shell. Below is a crude text diagram of what you're looking at:
__________ | | | | <-- lightening holes here | | leak here | | / _______| |__v____ ------------------------- -------- ^ Pressure wall here
The leak hole is in the flange of the C-channel, and the lightening hole (one of many, regularly spaced along the channel) is in the "vertical" wall of the C-channel. The "ragged" appearance of the lightening hole is actually residue from some tape that was covering the ring frame. You can see some of that tape at the bottom center of the image.