# Quicksync

### Introduction

The Cronos team has partnered with Chainlayer to provide the Quicksync service and make the process more efficient for our users.

Users can visit [Chainlayer QuickSync Cronos page](https://quicksync.io/cronos) and download the snapshots for Cronos Chain with different pruning settings.

{% hint style="info" %}
IMPORTANT

In order to use Quicksync you need to first complete [Step 3-2](https://docs.cronos.org/for-node-hosts/running-nodes/cronos-evm-snapshots/pages/FGCPNouBUvChBf1Hswy6#step-3-2.-run-everything) with the latest binary.

\
**Note** that as of `v0.9.0`, we have merged the binary to support both levelDB and rocksDB. Therefore, make sure to select the right [`app-db-backend`](https://github.com/crypto-org-chain/cronos/releases/tag/v1.0.2)in your `app.toml`.
{% endhint %}

### Step 1: Quicksync Download

After executing the command `./cronosd` start at [Step 3-2](https://docs.cronos.org/for-node-hosts/running-nodes/cronos-evm-snapshots/pages/FGCPNouBUvChBf1Hswy6#step-3-2.-run-everything) Run everything, it starts the node and syncs the blockchain data. When you see it starts to sync from 0, you can terminate the terminal.\
\
Both RocksDB and LevelDB snapshots are now available for Cronos Chain.

### Step 2: Quicksync Extract

To start with Quicksync, you need to run `brew install lz4` to install lz4 in a new terminal.\
Then download the file with preferred pruning settings directly from [Quicksync](https://quicksync.io/cronos).

### Step 3: Quicksync Setup

In the following steps, we will take as an example the version\
`cronosmainnet_25-1-pruned.20220309.2010.tar.lz4`.

* (Optional) you can download an addressbook from [Quicksync](https://quicksync.io/cronos) to get connected to peers faster. After downloading it, place the new `addrbook.json` under `.cronos/config` folder and restart your node to take effect.
* Now add the `cronosmainnet_25-1-pruned.20220309.2010.tar.lz4` inside `.cronos`

Then perform the following steps:

* Change the path under `.cronos` with `cd .cronos`
* Decompress with `lz4` and `tar` by `lz4 -d /Users/<username>/.cronos/cronosmainnet_25-1-pruned.20220308.2010.tar.lz4 | tar -xv`, as below:

{% hint style="info" %}
Example: Decompress the QuickSync pack with `lz4`

```bash
  x data/
  x data/application.db/
  x data/application.db/84856034.ldb
  x data/application.db/83264153.ldb
  ...
  x data/snapshots/metadata.db/CURRENT.bak
  x data/snapshots/metadata.db/MANIFEST-000107
  x data/snapshots/metadata.db/LOG
```

{% endhint %}

The original data folder under `.cronos` is overwritten with this step (it takes around 5-7 mins to decompress the pruned version \~50GB).

### Step 4: Sync with Quicksync

{% hint style="info" %}
Example: Restart `cronosd start` with QuickSync

```bash
  $ ./cronosd start
  6:59PM INF Unlocking keyring
  6:59PM INF starting ABCI with Tendermint
  6:59PM INF Starting multiAppConn service impl=multiAppConn module=proxy server=node
  6:59PM INF Starting localClient service connection=query impl=localClient module=abci-client server=node
  ...
  6:59PM INF ABCI Replay Blocks appHeight=1813707 module=consensus server=node stateHeight=1813707 storeHeight=1813707
```

{% endhint %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.cronos.org/for-node-hosts/running-nodes/cronos-evm-snapshots/quicksync.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.