Wait, how would you split 6 TiB across 6 phones, how would you handle the queries? How long will the data live, do you need to handle schema changes, and how? And what is the cost of a machine with 15 or 20 TiB of RAM (you said it fits in memory multiple times, right?) - isn’t the drive cost irrelevant here? How many requests per second did you specify? Isn’t that possibly way more important than data size? Awk on 6 TiB, even in memory, isn’t very fast. You might need some indexing, which suddenly pushes your memory requirement above 6 TiB, no? Do you need migrations or backups or redundancy? Those could increase your data size by multiples. I’d expect a question that specified a small data size to be asking me to estimate the real data size, which could easily be 100 TiB or more.