Ethereum Blobs Stored Temporarily for 18 Days

Ethereum's temporary data storage solution, blobs, are stored for approximately 18 days before nodes can prune the blob data. This is a key aspect of Ethereum's Layer 2 scaling strategy, known as EIP-4844 or Proto-Danksharding.

The protocol defines a minimum retention period of 4096 epochs, which translates to around 18.2 days under normal Ethereum timing. After this period, nodes are allowed to delete the actual blob data, but the transaction and commitment information associated with the blob remain part of the blockchain's history.

This temporary design is what allows blobs to provide relatively inexpensive data availability for Layer 2 rollups. The key distinction between blobs and calldata is that calldata becomes part of Ethereum's persistent historical transaction record, while blob contents are designed to be available only temporarily.