State-sync is a module built into the Cosmos SDK to allow validators to rapidly join the network by syncing your node with a snapshot enabled RPC from a trusted block height.
This greatly reduces the time required for a validator or sentry to sync with the network from days to minutes. The limitations of this are that there is not a full transaction history, just the most recent state that the state-sync RPC has stored. An advantage of state-sync is that the database is very small in comparison to a fully synced node, therefore using state-sync to re-sync your node to the network can help keep running costs lower by minimizing storage usage.
By syncing to the network with state-sync, a node can avoid having to go through all the upgrade procedures and can sync with the most recent binary only.
NOTE: For nodes that are intended to serve data for dapps, explorers, or any other RPC requiring full history, state-syncing to the network would not be appropriate.

Mainnet State Sync

Lavender.Five Nodes and SecretNFT are operating and maintaining the snapshot RPCs.
This documentation assumes you have followed the instructions for Running a Full Node.
The state-sync configuration is as follows:
# snapshot-interval specifies the block interval at which local state sync snapshots are
# taken (0 to disable). Must be a multiple of pruning-keep-every.
snapshot-interval = 2000
# snapshot-keep-recent specifies the number of recent snapshots to keep and serve (0 to keep all).
snapshot-keep-recent = 3

Assign And Verify Variables

Set the state-sync BLOCK_HEIGHT and fetch the TRUST_HASH from the snapshot RPC. The BLOCK_HEIGHT to sync is determined by finding the latest block that's a multiple of snapshot-interval.
BLOCK_HEIGHT=$(curl -s $SNAP_RPC/block | jq -r .result.block.header.height | awk '{print $1 - ($1 % 6000)}'); \
TRUST_HASH=$(curl -s "$SNAP_RPC/block?height=$BLOCK_HEIGHT" | jq -r .result.block_id.hash)
# output should be similar to:
# 3506000 FCB54D74A4A33F8C1CC18A7240D76D87CB192A89C17837C4DB6C6140612DDFEB74A4A33F8C1CC18A7240D76D87CB192A89C17837C4DB6C6140612DDFEB

Set Variables In ~/.secretd/config/config.toml

sed -i.bak -E "s|^(enable[[:space:]]+=[[:space:]]+).*$|\1true| ; \
s|^(rpc_servers[[:space:]]+=[[:space:]]+).*$|\1\",\"| ; \
s|^(trust_height[[:space:]]+=[[:space:]]+).*$|\1$BLOCK_HEIGHT| ; \
s|^(trust_hash[[:space:]]+=[[:space:]]+).*$|\1\"$TRUST_HASH\"|" $HOME/.secretd/config/config.toml

Reset Database And Stop Node

This will erase your node database. If you are already running validator, be sure you backed up your config/priv_validator_key.json and config/node_key.json prior to running unsafe-reset-all.
It is recommended to copy data/priv_validator_state.json to a backup and restore it after unsafe-reset-all to avoid potential double signing.
sudo systemctl stop secret-node && secretd tendermint unsafe-reset-all --home ~/.secretd/ --keep-addr-book

Set IAVL-disable-fastnode

IAVL fast node must be disabled, otherwise the daemon will attempt to upgrade the database while state sync is occuring.
sed -i.bak -e "s/^iavl-disable-fastnode *=.*/iavl-disable-fastnode = true/" ~/.secretd/config/app.toml

Restart Node And Check Logs

This generally takes several minutes to complete, but has been known to take up to 24 hours. To better help the process along, add seeds.
sudo systemctl restart secret-node && journalctl -fu secret-node
Expected State Sync Output