Historical data
This feature is available from Nimbus v23.1.0 onwards.
In order for the network to remain healthy, each node must keep a minimum of 5 months of historical block data.
Nimbus can be configured to either retain or remove historical data past that point using the --history option.
Default mode
Nimbus currently retains full history by default.
After the Capella hard fork, this will change to pruning.
History modes
The history mode controls how far back Nimbus supports answering historical queries in the REST API. It does not affect the ability to perform validator duties.
In prune mode, blocks and states past that point are removed from the database continuously and the freed space is reused for more recent data.
Info
Although blocks and states are pruned, the database will not shrink in size: instead, the freed space is reused for new data.
In archive mode, queries can be as far back as the state that the database was created with — the checkpoint state in the case of trusted node sync or genesis.
Switching between modes
It is possible to switch between prune and archive modes.
When switching to prune mode, deep history will be removed from the database and the prune point will be updated continuously as usual.
As noted above, the database will not shrink in size.
To reclaim space, perform a trusted node sync on a fresh database instead.
Backwards compatiblity
Versions prior to Nimbus v23.1.0 do not fully support pruned databases!
To downgrade, you may need to perform a trusted node sync.
When switching to archive mode, the node will start keeping history from the most recent prune point, but will not recreate deep history.
In order to recreate deep history in a pruned node, downloading the era archive of deep history and reindexing the database using trusted node sync with the --reindex option is necessary — this is a lengthy operation.