Yes, adding swap space should solve your problem on staging. On a production server I would give more RAM. We should not need 8GB, but somehow the memory usage creeps up over time. I hope we will solve that soon. @RohanM worked on that.
@maikel could you please note here or even better update the wiki page with what OS the server(s) are using? I think its good to know what options have been used.
The ofn_deployment notes mention Ubuntu PrecisePangolin but I’m wondering if new installs could use TrustyTahr? And current machines be updated?