Sync Options

When running a CKB full node, there are multiple ways to sync blockchain data to your local machine. Each method offers trade-offs between trust, performance, and convenience.

Option 1: Sync from P2P

This is the default and recommended approach, as described in Run a Mainnet Node.

How it works:

• Downloads blocks, headers, and state from other nodes over the P2P network.
• Validates each piece of data as it arrives.

ckb init --chain mainnet
ckb run

If you're using a Unix-like system, run ./ckb init --chain mainnet and ./ckb run instead.

Option 2: Copy Database + Replay

Used when you have access to a trusted, already-synced node, such as https://ckb-data.s3-accelerate.amazonaws.com/ckb-mainnet-0.201.0-2025-04-23.tar.gz.

How it works:

• You copy the entire data/ directory from a trusted node.
• ckb replay verifies the db integrity based on the local chain spec.

To verify the integrity of the data/ directory and write temporary output to the current directory, run:

ckb replay --tmp-target ./  --sanity-check

If you're using a Unix-like system, run ./ckb replay --tmp-target ./ --sanity-check instead. Note that the data/ directory must exist in your current directory. If it's located elsewhere, use -C <path> to point to the correct config directory.

Option 3: Import & Export

Use this method for backup or migrating chain data across machines.

How it works:

• ckb export saves the chain data from genesis to tip into a file.
• ckb import loads and re-validates that data into a new node.

Export

You need to shut down your node before running ckb export

ckb export --target mainnet_export.dat

You can name the file anything you like—mainnet_export is just an example. If you're using a Unix-like system, run ./ckb export --target mainnet_export.dat instead.

Import

ckb import <source-path>

<source-path> is the path to the .dat file you want to import. If you're using a Unix-like system, run ./ckb import <source-path> instead.

Comparison Summary

Method	Trust Model	Speed	Validation	Use Case
ckb run	Trustless	Slow	Full	First-time sync, safest and standard
ckb replay	Trusted source	Medium	Full	Internal sync, faster bootstrapping
ckb import/export	Portable file-based	Slow	Full	Migration, backup, offline sync