For 100TB you need a server, not a NAS appliance. If this is for a business, have them contact HP, Dell, Lenovo to spec out and support the system.
Aside from storing files, what else would the server be doing? Hosting an games, email systems, databases? Transcoding videos to other formats? How many users would be accessing the files simultaneously?
What about redundancy? Did you want the 100TB to be 10 individual drives or in some type of raid?
Expansion? How large might your storage needs grow to?