# Monero Blockchain Utilities
Copyright (c) 2014-2016, The Monero Project
## Introduction
The blockchain utilities allow one to import and export the blockchain.
## Usage:
See also each utility's "--help" option.
### Export an existing blockchain database
`$ monero-blockchain-export`
This loads the existing blockchain and exports it to `$MONERO_DATA_DIR/export/blockchain.raw`
### Import the exported file
`$ monero-blockchain-import`
This imports blocks from `$MONERO_DATA_DIR/export/blockchain.raw` (exported using the
`monero-blockchain-export` tool as described above) into the current database.
Defaults: `--batch on`, `--batch size 20000`, `--verify on`
Batch size refers to number of blocks and can be adjusted for performance based on available RAM.
Verification should only be turned off if importing from a trusted blockchain.
If you encounter an error like "resizing not supported in batch mode", you can just re-run
the `monero-blockchain-import` command again, and it will restart from where it left off.
```bash
## use default settings to import blockchain.raw into database
$ monero-blockchain-import
## fast import with large batch size, database mode "fastest", verification off
$ monero-blockchain-import --batch-size 20000 --database lmdb#fastest --verify off
```
### Import options
`--input-file`
specifies input file path for importing
default: `<data-dir>/export/blockchain.raw`
`--output-file`
specifies output file path to export to
default: `<data-dir>/export/blockchain.raw`
`--block-stop`
stop at block number
`--database <database type>`
`--database <database type>#<flag(s)>`
database type: `lmdb, berkeley, memory`
flags:
The flag after the # is interpreted as a composite mode/flag if there's only
one (no comma separated arguments).
The composite mode represents multiple DB flags and support different database types:
`safe, fast, fastest`
Database-specific flags can be set instead.
LMDB flags (more than one may be specified):
`nosync, nometasync, writemap, mapasync, nordahead`
BerkeleyDB flags (takes one):
`txn_write_nosync, txn_nosync, txn_sync`
```
## Examples:
$ monero-blockchain-import --database lmdb#fastest
$ monero-blockchain-import --database berkeley#fastest
$ monero-blockchain-import --database lmdb#nosync
$ monero-blockchain-import --database lmdb#nosync,nometasync
$ monero-blockchain-import --database berkeley#txn_nosync
```
