Data availability

A rollup must publish sufficient data under its security model. A specialized layer may use sampling and encoding to check availability without every node downloading everything.

In a rollup, participants need enough data to verify transitions or reconstruct state. Publishing only a root or proof does not necessarily supply that data. The publication location and mechanism affect system guarantees.

Ethereum blobs provide a temporary data channel, distinct from permanent contract storage. Historical retention requires additional infrastructure. Sampling, publication and archiving address related but different needs.