If you had tens of thousands of customers, would you bet your company on a homebrew MogileFS setup? And are you sure you'd save enough money to justify a port?
Yes. I'm confident in my abilities to overcome absolutely any problem that might occur. For the same reasons I choose Linux and open source solutions over Windows or other proprietary solutions: there's always a way out. Isilon, Cisco, or Oracle only provide the illusion of certainty.
Your confidence in your abilities provide only an illusion of certainty. Maybe if you had enough time you could fix any problems that occur with open source software, but when you have a deadline it's nice to have experts to help you. You can find open source experts, but with a commercially supported product there is a much clearer chain of responsibility.
While I support your argument, you have to be careful it doesn't turn into arrogance.
I remember one time being promised by the tech lead on a project that an inexpensive networking solution would be just as good as the expensive kit we had used for development. Turns out he couldn't make it work - the cheap kit just wasn't as good as the expensive stuff we had developed against.
However, I was the one standing in the customer's office being shouted at by three of their unhappy managers as their time critical project was delayed until we got the proper kit ordered and the tech lead sulked back at our office.
