Foundations
Expiring data
Data on Irys can be stored for 30 days, for a year, or permanently, and the price reflects the duration. The data is guaranteed for the length of the term and expires after it. This gives onchain data a lifecycle. Data can be created, extended while it is still needed, and allowed to expire when it is not. Inside the protocol, the 30-day and 1-year options are called term ledgers, and they arrived with the Cascade upgrade.
Why use term storage?
Term storage costs less. Permanent storage is priced for permanence, so every byte is paid for as if it will live for centuries. Not all data needs that. When data only has to last weeks or months, a term prices it for that window, and storage in the term ledgers costs considerably less than permanent storage.
Term data can also be updated over time. Suppose you keep 100 backup files on a 30-day term. Over the month, you create ten new files, and five of the old ones go out of date. When the term ends, you let those five expire, extend the other 95, and add the ten new ones. You are now paying for 105 files, all of them current, and none of them re-uploaded.
Data cannot be deleted early. It lives until at least the end of its term. In the example above, the update happens once a month because the term is 30 days. When a term ends, you choose what to extend, what to add, and what to let go.
What happens when data expires?
When data expires, the network stops paying for it. Miners on Irys earn rewards by proving they still hold the data they are responsible for, and proofs built on expired data stop counting. With no reward left for holding the expired chunks, miners eventually drop them and reclaim the space. The record that the data existed stays. Transaction headers and storage proofs remain in the blocks permanently, so anyone can check what was stored and when, long after the data itself is gone.
Does data expire exactly when the term ends?
No. The term is the minimum time your data is guaranteed to stay downloadable. After the term ends, miners eventually drop the data and reclaim the space, so it often remains available for a while longer. Pick a term based on how long you need the data guaranteed.
Is term data slower to retrieve?
No. Term data stays as fast as permanent data. Cheaper storage usually means slower retrieval, and archival systems keep low-cost data offline and take time to bring it back. Term data on Irys works differently. For its entire life it stays immediately downloadable through the gateway, because it is stored the same way permanent data is: the same partitions, the same miners, the same gateway. The lower price comes from the shorter commitment.
The term sets how long the data lives. It does not change how fast you can get it.