# Sync with state-sync

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 resync 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.

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.

### [#](https://docs.c4e.io/validatorsGuide/Starttestnet/state-sync.html#mainnet-state-sync)Testnet state-sync <a href="#mainnet-state-sync" id="mainnet-state-sync"></a>

Snapshot are operated on rpc1 and rpc2

<mark style="background-color:yellow;">WARNING: This documentation assumes you have followed all previous instructions</mark>

The state-sync configuration (in app.toml) is as follows *(no need to update it)*:

```
# 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 = 1000

# snapshot-keep-recent specifies the number of recent snapshots to keep and serve (0 to keep all).
snapshot-keep-recent = 10
```

Set `SNAP_RPC1` and `SNAP_RPC2` variable

```
SNAP_RPC1="https://rpc-archive-testnet.empe.io:443"
SNAP_RPC2="https://rpc-archive-testnet.empe.io:443"
```

Fetch the `LATEST_HEIGHT` from the snapshot RPC, set the state-sync `BLOCK_HEIGHT` and fetch the `TRUST_HASH` from the snapshot RPC. The `BLOCK_HEIGHT` to sync is determined by subtracting the snapshot-interval from the `LATEST_HEIGHT`.

```
LATEST_HEIGHT=$(curl -s https://rpc-archive-testnet.empe.io:443/block | jq -r .result.block.header.height); \
BLOCK_HEIGHT=$((LATEST_HEIGHT - 1000)); \
TRUST_HASH=$(curl -s "https://rpc-archive-testnet.empe.io:443/block?height=$BLOCK_HEIGHT" | jq -r .result.block_id.hash)
```

Check variables to ensure they have been set

<pre><code><strong>echo $LATEST_HEIGHT $BLOCK_HEIGHT $TRUST_HASH
</strong>
# output should be something similar to:
# 29604 28604 2BB3A74046C625CB67D477550D99F2439D48191FD0E840FA42A324B0629A612A
</code></pre>

Stop cosmovisor service

```
sudo systemctl stop cosmovisor
```

Set the required variables in `~/.emped/config/config.toml`

```
sed -i.bak -E "s|^(enable[[:space:]]+=[[:space:]]+).*$|\1true| ; \
s|^(rpc_servers[[:space:]]+=[[:space:]]+).*$|\1\"$SNAP_RPC1,$SNAP_RPC2\"| ; \
s|^(trust_height[[:space:]]+=[[:space:]]+).*$|\1$BLOCK_HEIGHT| ; \
s|^(trust_hash[[:space:]]+=[[:space:]]+).*$|\1\"$TRUST_HASH\"|" $HOME/.empe-chain/config/config.toml

```

Reset the node database

<mark style="background-color:yellow;">WARNING: 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\` before running \`unsafe-reset-all\`.</mark>

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.

```
emped tendermint unsafe-reset-all --home $HOME/.empe-chain
```

Restart the node and check the logs

```
sudo systemctl restart cosmovisor && journalctl -u cosmovisor -f

```