Crypto glossary
PeerDAS
PeerDAS (peer data availability sampling) lets Ethereum nodes confirm rollup blob data is available by storing and sampling only part of it from peers.
PeerDAS, specified in EIP-7594, went live with the Fusaka upgrade in December 2025. Blob data is extended with erasure coding and split into columns. Each node keeps custody of a subset of columns and asks peers for random samples of others. Because any half of the extended data is enough to rebuild the whole, a node that gets its samples can be confident the full blob set was published without downloading it.
Before PeerDAS, every consensus node had to download every blob, so raising blob capacity raised bandwidth for home validators too. Splitting the work lets Ethereum increase the number of blobs per block, and Fusaka paired it with small follow-up forks that only adjust blob parameters. For rollups, more blob space means more room for cheap data posting as demand grows.
PeerDAS is a step toward full danksharding, not the end state. Nodes that run many validators are expected to custody more data, block builders and proposers still handle the full blobs, and the security of sampling depends on a healthy, well-connected peer network.
Example
After Fusaka, a home staker notices that their node's bandwidth barely changed even though the network's blob target was raised, because PeerDAS only asks it to store some columns.