If it will be a closed platform, it doesn't matter. I had a lot of experience with Solaris (x86 only - people tried to run Informix/Oracle on a cheap hardware

If it will be a closed platform, it doesn't matter. I had a lot of experience with Solaris (x86 only - people tried to run Informix/Oracle on a cheap hardware) starting from Solaris 7 and onwards. It was always a problem even to install it. And lack of working compiler makes things even worse. Starting from Solaris 10 they did a lot of work to improve the overall experience, but too late - everyone migrated to Linux to run the same crap. And I must say, that after it was installed and tuned it was running quite stable as a database server and it can deal with heavy loads, while similar Linux instances failed now and then. But it was 5 years ago. Modern Linux kernels can handle everything quite well.