snapshots.md

Index Snapshots

This document describes index snapshots, what they are and how they can be created and restored.

Table of Contents

• What Are Index Snapshots
• Creating a Snapshot
• Restoring a Snapshot

What Are Index Snapshots

Index snapshots are images of the DPS index database. These images can be used to easily transfer DPS index snapshots as a single file or to archive them in a more space-efficient manner. They can also be used in testing, so that tests have actual blocks, accounts, transactions and other information to operate on.

At a low level, snapshots are created using the badger backup functionality. Technical documentation can be found here.

Creating a Snapshot

Index snapshots are created using create-index-snapshot CLI tool, which is documented here. By default, the snapshot is not encoded and output contains raw (binary) data.

$ create-index-snapshot -i <index_dir> > output.bin

When an index snapshot is created, it can be compressed with a specific compression algorithm (zstd or gzip). When restoring the index, the snapshot needs to be decompressed using the same algorithm or the snapshot restore will fail.

Restoring a Snapshot

Restoring snapshots is done using the restore-index-snapshot CLI tool, which is documented here. To successfully restore the snapshot, you must specify the compression and encoding options that were used to create it.

Example of restoring a gzip compressed snapshot:

$ restore-index-snapshot -i /var/dps/index -c gzip < dps-index-snapshot.gz