The article says, > At peak times, Cash App's database handles approximately 3–4 million queries per second (QPS) across 400 shards, totaling around 400TiB of

The article says, > At peak times, Cash App's database handles approximately 3–4 million queries per second (QPS) across 400 shards, totaling around 400TiB of data. 400TiB represents not a lot of this data. If each query stored only 1 byte, this would only be 4 years worth of this data. If duplicated, or processed and the results stored, that would add up, too.