Work out data lake storage cost instantly with clear inputs, formula shown and shareable results.
A data lake reaches steady state at monthly ingest times retention, so 80 TB monthly with three years of retention holds 2.9 PB raw. Converting to a columnar format such as Parquet with compression typically achieves five-to-one or better, cutting that to under 600 TB — and the same conversion reduces query scan cost proportionally.
Lake storage
compressed per month = raw / compression ratio; steady state = compressed x retention months; cost = TB x 1000 x per-GB rate
Values in a column share a type and often repeat, so dictionary encoding, run-length encoding and delta encoding all apply. Row formats mix types and compress far worse.
Often yes for reprocessing, but in the cheapest archive tier. Keeping raw JSON in standard storage alongside Parquet doubles cost for little benefit.