What is MySQL Cluster's Practical Memory Limit?
As I read it, there is a 64GB limit per node.  48 nodes, without redundancy, would allow 3TB total data size, 1.5TB with redundancy.

That sounds like less than a day's worth of data at the rate you are ingesting data.

Do you need all the raw data?  Or can you summarize the data, then throw away (or archive to text files) the raw data?  This would probably let you collect data for 10 times as long.