Rails Server unable to run commands as daemon

I am running rails server as a daemon on ubuntu server.
My controller uses `#{command}` to run a python image processor and
return the output.
After several requests and hours of uptime the server stops working
when it hits this command, stating that it got no output. But the
command runs fine on the server when logged in via ssh.
The server has plenty of memory, and any of the three requests that
require running an external command at this point fail until the
server is restarted - but the server spits out all other pages on the
site just fine.
I think something to do with stdout or stderr is to blame, but I'm not
sure. Anyone have any ideas?

It might be worth changing from using backticks to using IO.popen or
Open3.popen3 - just as a generally preferred method of running system
calls, which might squash your bug at the same time.