Unfortunately the linux server just has not been reliable for Arma 2 OA with the Insurgency map. When testing with a few players the server would just crash with no errors as such. The test linux server was a VPS solution so I wonder if that might be the problem. I'm going to contact a few of the linux server admins and see what systems they use and if they have had the same problems?
For the moment I've switched back to a Windows system but lowered the player limit to only 5 for now and will look into increasing the processor/memory share to add some additional players tomorrow.