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Import ERA1 files

When running full sync, node operators can optionally import pre-merge block history from locally stored or remote ERA1 archive files. This method allows nodes to bootstrap pre-merge Ethereum data without relying on peer-to-peer downloads.

ERA1 file import must be explicitly enabled by including the following command line options:

besu --era1-import-prepipeline-enabled --era1-data-uri=<PATH-OR-URI> --era1-import-prepipeline-concurrency=1

In the command:

  • --era1-import-prepipeline-enabled enables importing pre-merge blocks from ERA1 archive files before full synchronization begins. This option only applies in FULL sync mode.
  • --era1-data-uri specifies the location of the ERA1 files to be imported. Either a simple filesystem path (/path/to/files/), or an HTTP address (https://mainnet.era1.nimbus.team). The default is https://mainnet.era1.nimbus.team.
  • --era1-import-prepipeline-concurrency sets the number of parallel processes used to import ERA1 files. The default is 1. Increase only if you encounter slow file download speeds and your system can handle additional load.

After all ERA1 files are imported, Besu automatically continues with full synchronization to complete syncing the rest of the chain.