Configure History Sharding

History Sharding lets servers contribute to preserving historical XRP Ledger data without each server needing to store the full history. By default, rippled servers do not store history shards.

To configure your rippled to store shards of ledger history, complete the following steps:

1. Determine how many shards to maintain

Before you configure your rippled server to store history shards, you must decide how many history shards you want to keep, which is mostly determined by how much disk space is available for the shard store. This also affects how much history you keep in the default ledger store. You should consider the following when deciding what size to configure your shard store:

• The ledger store (defined by the [node_db] stanza) is separate from the history shard store. The ledger store is required for all servers, and always contains a range of recent history, defined by how many ledgers to keep available in the online_delete parameter. (The default configuration stores the most recent 2000 ledgers.)
  • If you keep at least 2¹⁵ ledgers (32768) in the ledger store, you can efficiently import chunks of recent history from the ledger store into the shard store.
• The history shard store (defined by the [shard_db] stanza) is only required for storing history shards. The configuration stanza should be omitted from servers that do not store history shards. The total number of shards stored is defined by the max_historical_shards parameter; the server attempts to store no more than this many complete shards. The history shard store MUST be stored on a solid-state disk or similar fast media. Traditional spinning hard disks are insufficient.
• A shard consists of 2¹⁴ ledgers (16384) and occupies approximately 200 MB to 4 GB based on the age of the shard. Older shards are smaller because there was less activity in the XRP Ledger at the time.
• The history shard store and the ledger store MUST be stored at different file paths. You can configure the ledger store and history store to be on different disks or partitions if desired.
• It is possible but redundant to hold full ledger history in both the ledger store and the history shard store.
• The time to acquire a shard, number of file handles needed by the rippled server, and memory cache usage is directly affected by the size of the shard.
• You can specify additional paths to store older history shards by providing a [historical_shard_paths] stanza. These paths may be on different, slower disks because they hold data that is used less often. The most recent two shards (the ones with the largest ledger indexes) are always stored in the path specified in the [shard_db] stanza.

2. Edit rippled.cfg

Edit your rippled.cfg file to add a [shard_db] stanza and optionally a [historical_shard_paths] stanza.

The recommended installation uses the config file /etc/opt/ripple/rippled.cfg by default. Other places you can put a config file include $HOME/.config/ripple/rippled.cfg (where $HOME is the home directory of the user running rippled), $HOME/.local/ripple/rippled.cfg, or the current working directory from where you start rippled.

The following snippet shows an example of a [shard_db] stanza:

[shard_db]
path=/var/lib/rippled/db/shards/nudb
max_historical_shards=12

# Optional paths for shards other than the newest 2
[historical_shard_paths]
/mnt/disk1
/mnt/disk2

The type field of [shard_db] can be omitted. If present, it MUST be NuDB.

For more information, reference the [shard_db] example in the rippled.cfg configuration example.

3. Restart the server

systemctl restart rippled

4. Wait for shards to download

After your server syncs to the network, it automatically starts downloading history shards to fill the available space in the shard store. You can see which shards are being downloaded by looking at which folders are created in the folder where you configured your shard store. (This is defined by the path field of the [shard_db] stanza in the rippled.cfg file.)

This folder should contain a numbered folder for each shard your server has. At any given time, up to one folder may contain a control.txt file, indicating it is incomplete.

You can instruct your server to download and import a shard from an archive file using the download_shard method.

To list the shards your server and its peers have available, you can use the crawl_shards method or the Peer Crawler.

See Also

• Concepts:
  • Ledger History
    • Online Deletion
• Tutorials:
  • Configure Online Deletion
  • Configure the Peer Crawler
  • Capacity Planning
• References:
  • download_shard method
  • crawl_shards method
  • Ledger Data Formats