Server side rendering only makes sense if the scene consists of a huge number of objects such that the download of the data set to the client for client rendering would be far too slow and the rendering is not expected to be in realtime. Client side rendering isn't too difficult if you use something like jogl coupled with progressive scene download (i.e. download foreground objects and render, then incrementally download objects based on distance from view point and re-render).
If you really want to do server side rendering, you may want to separate the web server part and the rendering part onto two computers with each configured optimally for their task (renderer has OpenGL card, minimal HD and just enough RAM, server has lots of fast disks, lots of ram, backups and no OpenGL). I very much doubt you will be able to do hardware rendering on a virtualised server since the server probably doesn't have a GPU.
