> For the complete documentation index, see [llms.txt](https://docs.zklink.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zklink.io/architecture/da-layer.md).

# DA Layer

The DA Layer entails making the transaction and state data available. 

Nova chooses the **Validium mode** for storing data. Under classic Rollup mode, the majority of Ethereum gas costs go to Data Availability, and not proof verification. This is because it is very gas-intensive to store data on Ethereum. In Validium mode, Nova's data is stored off-chain with a Data Availability Committee (DAC). This Data Availability Committee oversees the correct state update as well as keep a copy of the data that was processed.

In the very near future, Nova will integrate with external DA solutions, for example, Celestia, EigenDA, Avail, etc., so that data will be stored in a more decentralized approach with censorship resistence.

  


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