If I had the opportunity to do so I would always look for a minimum of 2 sites, with sufficient hardware at each to use 1/2 each site for production, the other 1/2 for dev & test. In a DR scenario I would only have to recover 1/2 my kit, whilst getting the added benefit of dev & test kit that is on a par with the production environment
Kind Regards,
Matthew Bourne
"Find a job you love and never do a day's work in your life.