You'd think that with a price tag of billions of dollars the LHC would have more storage capacity than it could ever use. But with the machine producing a petabyte of data every second, the researchers simply can't store it all.
To put that into perspective, a petabyte is a million gigabytes, or enough capacity to store 13.3 years of HDTV content. And that's how much data the LHC's sensors are producing every second during an experiment. That's insane, and understandably, the facility simply doesn't have the capacity to save all that data.