📦 Using Jovay Ledger Snapshots

📖 Introduction

Jovay publishes Sequencer ledger snapshots on a regular schedule so you can bootstrap nodes—especially a State Derivation (SD) Sequencer—from recent rollup state without syncing the full chain history.

Each release ships three artifacts for a given network:

Artifact	Description
📜 genesis.conf	Fixed genesis configuration for the network (same file for every release on that network).
🗜️ <YYYYMMDD>_<BLOCK_HEIGHT>.tar.gz	Compressed ledger database snapshot.
⚓ snapshot_anchor.json	L1 cursor seed for State Derivation. The current implementation begins scanning from the following L1 block.

Archive names follow YYYYMMDD_BLOCKHEIGHT.tar.gz (YYYYMMDD = publish date, BLOCK_HEIGHT = L2 stable height in the snapshot). The matching anchor is published at state-derivation/YYYYMMDD_BLOCKHEIGHT/snapshot_anchor.json.

📌 Retention: Only the latest snapshot per network is kept on the CDN. Older archives are removed when a new one is published.

⏱️ Cadence: Snapshots are published approximately every 14 days.

💾 Capacity planning: The current Testnet archive is about 126 GiB compressed and expands to about 360 GiB. Keep the archive and extracted ledger on the same filesystem only if it has at least 600 GiB free, including room for database growth. Snapshot sizes will increase as the chain grows.

🎯 What You Need From a Snapshot

Before starting an SD Sequencer, download all three artifacts for your target network from the table below:

1. ✅ genesis.conf
2. ✅ Latest <YYYYMMDD>_<BLOCK_HEIGHT>.tar.gz
3. ✅ Matching snapshot_anchor.json

✅ Recommended image: Use product version 0.15.0, published as jovay-release-registry.cn-hongkong.cr.aliyuncs.com/jovay/l2-sequencer:0.15.0-rc1. This exact tag has been validated end to end with the current Testnet snapshot.

📊 Latest Jovay Ledger Snapshots

Testnet (Sepolia L1)

File	Recommended Sequencer version	L2 block height	File name	Checksums	Download
📜 genesis.conf	0.15.0-rc1	—	genesis.conf	MD5: 1b6ad3d9fa67a596ca094e89bd2280ee SHA-256: 772cdd59b915787a5bca57f7bba0584333081f8749a7f702f5bba60819000fad	link
🗜️ Ledger snapshot	0.15.0-rc1	46787372	20260916_46787372.tar.gz	MD5: 16212a19ffa5c6b1d871bb7c9f23a9c6 SHA-256: 95f502b62e2ea7982cfe9006d4b087d840984db9bfed23c4a7fd3314d850e40e	link
⚓ snapshot_anchor.json	0.15.0-rc1	46787372	snapshot_anchor.json	MD5: 478e9f5175cb3ea659b0eceddc5a23d3 SHA-256: 4beedfd0e2147a97eb34e847a06b74c7b62adf64952f3f41f11cfe2a08183ee1	link

Mainnet (Ethereum L1)

File	Recommended Sequencer version	L2 block height	File name	Checksums	Download
📜 genesis.conf	0.15.0-rc1	—	genesis.conf	MD5: 502c910cbc21137c606621622fe67d28 SHA-256: d436f01b2e25d1946e63d885cb1dd3136da0e3d3beaf300f6f3f4482aff6b5d9	link
🗜️ Ledger snapshot	—	—	Not available yet	—	Not available yet
⚓ snapshot_anchor.json	—	—	Not available yet	—	Not available yet

⚠️ The Mainnet ledger snapshot and matching anchor have not been published yet. Do not start a Mainnet SD Sequencer until both rows above contain a real release.

After downloading all three artifacts, verify each file's SHA-256 checksum against the table above. MD5 values are retained for compatibility and accidental-transfer checks, but SHA-256 is the primary integrity check:

sha256sum genesis.conf
sha256sum <YYYYMMDD>_<BLOCK_HEIGHT>.tar.gz
sha256sum snapshot_anchor.json

# Optional compatibility check
md5sum genesis.conf <YYYYMMDD>_<BLOCK_HEIGHT>.tar.gz snapshot_anchor.json

🗂️ Snapshot Archive Structure

The archive has one top-level public/ directory. It contains 11 database directories and no loose files at that level:

Example (tree -L 1 public after extraction):

public/
├── BlockBodySliceKvDB
├── BlockHeaderKvDB
├── BlockIndexKvDB
├── BlockMetaKvDB
├── BlockRwSetDB
├── ContractCodeKvDB
├── MetaKvDB
├── PersistTxKvDB
├── ProofKvDB
├── StateDB
└── TxIndexKvDB

11 directories, 0 files

When deploying an SD Sequencer, extract these folders into data/public/ — see Start a State Derivation Sequencer.

⚓ snapshot_anchor.json Format

{
  "l1_start_block_number": 24933000
}

Field	Description
l1_start_block_number	Initial value of the persisted L1 indexer cursor. The current implementation scans from l1_start_block_number + 1. Always use the snapshot_anchor.json published with your snapshot—do not guess or edit this value.

🚀 Next Steps

Ready to run a node? Continue with Start a State Derivation Sequencer.

For Jovay RPC URLs and chain IDs, see Network Information.