Data directory

The data directory contains or might contain:

bitcoin.conf
wallet.dat
peers.dat: The IP-address database, accessed via class CAddrDB, src/addrdb.h. Apparently, peers.dat replaced addr.dat in version 0.7.0.
banlist.dat: The banlist database, accessed via class CBanDB, src/addrdb.h
fee_estimates.dat
mempool.dat
db.log: The error file for the wallet database (Berkeley DB). (See CDBEnv::Open, src/wallet/db.cpp).
debug.log
.lock (created(?) by LockDataDirectory() in src/init.cpp

Directory blocks

The blocks directory within the data directory contains:

index: This subdirectory is a LevelDB database (managed through CDBWrapper) that helps find blocks (blk*.dat files?) on the harddisk.. Apparently, this directory is managed by CBlockTreeDB.
blk*.dat which are block files. Used for 1) rescanning missing transactions in a wallet 2) reorganizing to a different part in the blockchain 3) serving block data to other nodes that are synchronizing
rev*.dat which are undo files

Directory chainstate

The chainstate directory is a LevelDB database and managed by CDBWrapper.

It represents all currently unspent transactions along with some information where these transactions come from.

Using this database speeds up validation of transactions. Without this database, such a validation would also be possible, but the entire block-data would have to be scanned for every output being spent.

The data could be rebuilt from the block data which. However, that takes a long time. (See -reindex command line flag).

src/txdb.h contains the following comment:

CCoinsView backed by the coin database (chainstate)

Testnet

If bitcoin-qt is run with -testnet, it creates the directory testnet3 under the data diretory.

testnet3 then contains the same files (with different content) as the data directory.

Data directory

Directory blocks

Directory chainstate

Testnet

Scrambling data

See also

Links