I don't know why this happened, so I think this might be a bug in FreeBSD 10.3-p11. For some reason my server ran out of swap space while updating ports that where compiling, this resulted in a freeze and I had to hard reboot the computer. It seems that swamp is not cleaned of old items and over a long period or heavy that resulted filled up swamp area (around 10GB in size).
I don't know why the FreeBSD did freeze, this computer has 8GB of ram installed.
I don't know why the FreeBSD did freeze, this computer has 8GB of ram installed.