> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/bitcoin/bitcoin/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Directory Structure

> Complete guide to Bitcoin Core data directory layout, file locations, and storage requirements

The data directory is the default location where Bitcoin Core stores all blockchain data, wallet files, configuration, and other runtime files.

## Data Directory Location

### Default Paths

The default data directory varies by operating system:

| Platform | Default Path                             |
| -------- | ---------------------------------------- |
| Linux    | `~/.bitcoin/`                            |
| macOS    | `~/Library/Application Support/Bitcoin/` |
| Windows  | `%LOCALAPPDATA%\Bitcoin\`                |

### Custom Data Directory

You can specify a custom data directory using the `-datadir` option:

```bash theme={null}
bitcoind -datadir=/mnt/bitcoin
bitcoin-qt -datadir=/custom/path
```

## Chain-Specific Directories

All content except `bitcoin.conf` is chain-specific. The actual data directory path differs based on the network:

| Chain Option                     | Subdirectory Path     |
| -------------------------------- | --------------------- |
| `-chain=main` (default)          | `<datadir>/`          |
| `-chain=test` or `-testnet`      | `<datadir>/testnet3/` |
| `-chain=testnet4` or `-testnet4` | `<datadir>/testnet4/` |
| `-chain=signet` or `-signet`     | `<datadir>/signet/`   |
| `-chain=regtest` or `-regtest`   | `<datadir>/regtest/`  |

<Note>
  When using testnet, your data is stored in a `testnet3/` subdirectory, not at the root of the data directory.
</Note>

## Directory Structure

### Root Directory Files

<ParamField path="bitcoin.conf" type="file">
  User-defined configuration settings. Not written by the software, must be created manually.

  **Location:** `<datadir>/bitcoin.conf`
</ParamField>

<ParamField path="settings.json" type="file">
  Dynamic settings set through GUI or RPC interfaces. Created automatically unless disabled with `-nosettings`.

  **Location:** `<datadir>/settings.json`
</ParamField>

<ParamField path="debug.log" type="file">
  Debug information and general logging. Can be configured with `-debuglogfile` option.

  **Location:** `<datadir>/debug.log`
</ParamField>

<ParamField path="bitcoind.pid" type="file">
  Process ID file. Created at start, deleted on shutdown.

  **Location:** `<datadir>/bitcoind.pid`
</ParamField>

<ParamField path=".cookie" type="file">
  Session RPC authentication cookie. Created at start if used, deleted on shutdown.

  **Location:** `<datadir>/.cookie`
</ParamField>

<ParamField path=".lock" type="file">
  Data directory lock file to prevent multiple instances.

  **Location:** `<datadir>/.lock`
</ParamField>

### Network and Peer Files

<ParamField path="peers.dat" type="file">
  Peer IP address database in custom format.

  **Location:** `<datadir>/peers.dat`
</ParamField>

<ParamField path="anchors.dat" type="file">
  Anchor IP address database. Created on shutdown, deleted at startup. Contains last known outgoing block-relay-only peers.

  **Location:** `<datadir>/anchors.dat`
</ParamField>

<ParamField path="banlist.json" type="file">
  Stores the addresses/subnets of banned nodes.

  **Location:** `<datadir>/banlist.json`
</ParamField>

### Mempool and Fee Estimation

<ParamField path="mempool.dat" type="file">
  Dump of the mempool's transactions. Saved on shutdown if `-persistmempool=1`.

  **Location:** `<datadir>/mempool.dat`
</ParamField>

<ParamField path="fee_estimates.dat" type="file">
  Statistics used to estimate minimum transaction fees required for confirmation.

  **Location:** `<datadir>/fee_estimates.dat`
</ParamField>

### Privacy Network Keys

<ParamField path="onion_v3_private_key" type="file">
  Cached Tor v3 onion service private key for `-listenonion` option.

  **Location:** `<datadir>/onion_v3_private_key`
</ParamField>

<ParamField path="i2p_private_key" type="file">
  Private key for I2P address. Used when `-i2psam=` is specified. Auto-generated if it doesn't exist.

  **Location:** `<datadir>/i2p_private_key`
</ParamField>

## Blockchain Data Directories

### blocks/

Contains all blockchain block data. Can be relocated with `-blocksdir` option.

<ParamField path="blocks/blkNNNNN.dat" type="file">
  Actual Bitcoin blocks in network format. NNNNN is a 5-digit number (e.g., `blk00000.dat`). Each file is up to 128 MiB.

  **Location:** `<datadir>/blocks/blk*.dat`
</ParamField>

<ParamField path="blocks/revNNNNN.dat" type="file">
  Block undo data in custom format. Used to disconnect blocks during reorg.

  **Location:** `<datadir>/blocks/rev*.dat`
</ParamField>

<ParamField path="blocks/xor.dat" type="file">
  Rolling XOR pattern for block and undo data files (obfuscation layer).

  **Location:** `<datadir>/blocks/xor.dat`
</ParamField>

<ParamField path="blocks/index/" type="directory">
  LevelDB database containing block index. Not affected by `-blocksdir` option.

  **Location:** `<datadir>/blocks/index/`
</ParamField>

### chainstate/

<ParamField path="chainstate/" type="directory">
  LevelDB database containing blockchain state. This is a compact representation of all currently unspent transaction outputs (UTXOs) and metadata.

  **Location:** `<datadir>/chainstate/`
</ParamField>

## Optional Indexes

These directories only exist if the corresponding index is enabled.

### Transaction Index

<ParamField path="indexes/txindex/" type="directory">
  LevelDB database for transaction index. Created when `-txindex=1` is set.

  **Location:** `<datadir>/indexes/txindex/`
</ParamField>

### Transaction Spender Index

<ParamField path="indexes/txospenderindex/" type="directory">
  LevelDB database for transaction output spender index. Created when `-txospenderindex=1` is set.

  **Location:** `<datadir>/indexes/txospenderindex/`
</ParamField>

### Block Filter Index

<ParamField path="indexes/blockfilter/basic/db/" type="directory">
  LevelDB database for basic block filters. Created when `-blockfilterindex=basic` is set.

  **Location:** `<datadir>/indexes/blockfilter/basic/db/`
</ParamField>

<ParamField path="indexes/blockfilter/basic/fltrNNNNN.dat" type="file">
  Block filter data files for basic filtertype.

  **Location:** `<datadir>/indexes/blockfilter/basic/fltr*.dat`
</ParamField>

### Coin Stats Index

<ParamField path="indexes/coinstatsindex/db/" type="directory">
  LevelDB database for coin statistics index. Created when `-coinstatsindex=1` is set.

  **Location:** `<datadir>/indexes/coinstatsindex/db/`
</ParamField>

## Wallet Directory

### Multi-Wallet Environment

<ParamField path="wallets/" type="directory">
  Contains wallet files. Can be relocated with `-walletdir` option. If the directory doesn't exist, wallets reside in the data directory root.

  **Location:** `<datadir>/wallets/`
</ParamField>

Wallet files are SQLite databases (as of recent versions):

* Named wallets: `wallets/<wallet_name>/wallet.dat`
* Default wallet: `wallets/wallet.dat`

### SQLite Wallet Files

<ParamField path="wallets/*/wallet.dat" type="file">
  Personal wallet database containing keys and transactions (SQLite format).

  **Location:** `<datadir>/wallets/<name>/wallet.dat`
</ParamField>

<ParamField path="wallets/*/wallet.dat-journal" type="file">
  SQLite rollback journal file. Created during transactions. Must be kept as safe as `wallet.dat`.

  **Location:** `<datadir>/wallets/<name>/wallet.dat-journal`
</ParamField>

<Warning>
  `wallet.dat` files must not be shared across different node instances. This can result in key-reuse and double-spends due to lack of synchronization.
</Warning>

<Info>
  Always use the `backupwallet` RPC command to back up wallets. This ensures the wallet is properly locked and updated before copying.
</Info>

## GUI Settings

<ParamField path="guisettings.ini.bak" type="file">
  Backup of former GUI settings after `-resetguisettings` option is used.

  **Location:** `<datadir>/guisettings.ini.bak`
</ParamField>

`bitcoin-qt` uses Qt's `QSettings` class for GUI preferences. Settings location is platform-specific:

* **Linux:** `~/.config/Bitcoin/Bitcoin-Qt.conf`
* **macOS:** `~/Library/Preferences/org.bitcoin.Bitcoin-Qt.plist`
* **Windows:** Registry or `%APPDATA%\Bitcoin\`

## Storage Requirements

### Full Node (Non-Pruned)

As of 2026, a full archival node requires:

* **Blockchain data:** \~600+ GB (growing continuously)
* **chainstate:** \~10-15 GB
* **Transaction index:** \~50-100 GB (if enabled)
* **Total:** \~650-750+ GB

### Pruned Node

With pruning enabled:

```bash theme={null}
bitcoind -prune=550  # Minimum
bitcoind -prune=10000  # 10 GB
```

* **Minimum:** 550 MB (blocks) + \~10 GB (chainstate) = \~11 GB
* **Custom:** Specified size + chainstate

<Note>
  Pruned nodes cannot serve historical blocks to other peers and cannot use `-txindex`.
</Note>

## Legacy Files and Directories

These are no longer used by current Bitcoin Core versions:

| Path                | Replaced By            | Last Used |
| ------------------- | ---------------------- | --------- |
| `banlist.dat`       | `banlist.json`         | v22.0     |
| `blktree/`          | `blocks/index/`        | v0.8.0    |
| `coins/`            | `chainstate/`          | v0.8.0    |
| `blkindex.dat`      | Multiple files         | v0.8.0    |
| `blk000?.dat`       | `blkNNNNN.dat`         | v0.8.0    |
| `addr.dat`          | `peers.dat`            | v0.7.0    |
| `onion_private_key` | `onion_v3_private_key` | v0.21.0   |
| `database/` (BDB)   | SQLite wallets         | v23.0+    |

## Filesystem Recommendations

<Warning>
  On macOS, avoid using the `exFAT` filesystem for the data directory or blocks directory. Multiple reports indicate database corruption and data loss with this filesystem. See [Bitcoin Core Issue #31454](https://github.com/bitcoin/bitcoin/issues/31454).
</Warning>

Recommended filesystems:

* **Linux:** ext4, XFS, Btrfs
* **macOS:** APFS, HFS+
* **Windows:** NTFS

## Best Practices

### Separate Volumes

For better performance and management:

```bash theme={null}
# Put blocks on separate fast storage
bitcoind -datadir=/var/lib/bitcoin -blocksdir=/mnt/fast-storage/blocks

# Put wallets on secure storage
bitcoind -walletdir=/mnt/secure/wallets
```

### Backup Strategy

1. **Configuration:** Back up `bitcoin.conf`
2. **Wallets:** Use `backupwallet` RPC command regularly
3. **Blockchain:** No backup needed (can be re-downloaded)
4. **Optional:** Back up `fee_estimates.dat` for faster startup

### Monitoring Disk Usage

```bash theme={null}
# Check data directory size
du -sh ~/.bitcoin

# Check blocks directory
du -sh ~/.bitcoin/blocks

# Check chainstate size
du -sh ~/.bitcoin/chainstate
```

## File Permissions

<Warning>
  Ensure proper file permissions to protect sensitive data:
</Warning>

```bash theme={null}
# Secure the entire data directory
chmod 700 ~/.bitcoin

# Wallet files should be especially protected
chmod 600 ~/.bitcoin/wallets/*/wallet.dat

# Configuration file
chmod 600 ~/.bitcoin/bitcoin.conf
```

## See Also

* [bitcoin.conf Configuration File](/configuration/bitcoin-conf) - Configuration file format and options
* [Command-Line Options](/configuration/command-line-options) - All available command-line arguments