Trade off between (physical space = delivery cost, ping) and bandwidth. A suit case can easily fit 20 1TB drives. A 20 hour journey from Sydney to London, would mean a transfer rate of 1TB per hour, or 2000+ megabits per second, or 300x faster than the internet in my own home. Even carrying only 1 terabyte over 20 hours is a decent 111 megabits&#x2F;second.