State Sync allows a new node to join the network by fetching a snapshot of the application state at a recent height instead of fetching and replaying all historical blocks. Since the application state is generally much smaller than the blocks, and restoring it is much faster than replaying blocks, this can reduce the time to sync with the network from days to minutes.

Stop the service and reset the data

sudo systemctl stop zenrock-testnet.service
cp $HOME/.zrchain/data/priv_validator_state.json $HOME/.zrchain/priv_validator_state.json.backup
zenrockd comet unsafe-reset-all --keep-addr-book --home $HOME/.zrchain

Get and configure the state sync information

STATE_SYNC_RPC=https://zenrock-testnet.rpc.kjnodes.com:443
STATE_SYNC_PEER=d5519e378247dfb61dfe90652d1fe3e2b3005a5b@zenrock-testnet.rpc.kjnodes.com:18256
LATEST_HEIGHT=$(curl -s $STATE_SYNC_RPC/block | jq -r .result.block.header.height)
SYNC_BLOCK_HEIGHT=$(echo "$LATEST_HEIGHT" | awk '{printf "%d000\n", $0 / 1000}')
SYNC_BLOCK_HASH=$(curl -s "$STATE_SYNC_RPC/block?height=$SYNC_BLOCK_HEIGHT" | jq -r .result.block_id.hash)

sed -i \
  -e "s|^enable *=.*|enable = true|" \
  -e "s|^rpc_servers *=.*|rpc_servers = \"$STATE_SYNC_RPC,$STATE_SYNC_RPC\"|" \
  -e "s|^trust_height *=.*|trust_height = $SYNC_BLOCK_HEIGHT|" \
  -e "s|^trust_hash *=.*|trust_hash = \"$SYNC_BLOCK_HASH\"|" \
  -e "s|^persistent_peers *=.*|persistent_peers = \"$STATE_SYNC_PEER\"|" \
  $HOME/.zrchain/config/config.toml

mv $HOME/.zrchain/priv_validator_state.json.backup $HOME/.zrchain/data/priv_validator_state.json

(Optional) Download latest wasm

If the chain does not support copy of the wasm folder, you can download it manually.

curl -L https://snapshots.kjnodes.com/zenrock-testnet/wasm_latest.tar.lz4 | lz4 -dc - | tar -xf - -C $HOME/.zrchain

Restart the service and check the log

sudo systemctl start zenrock-testnet.service && sudo journalctl -u zenrock-testnet.service -f --no-hostname -o cat