Repository Configuration

This guide covers how to configure rustic_core repositories, including initialization options, repository-wide settings, and environment variables.

Overview

rustic_core repositories can be configured at multiple levels:

Repository initialization - Settings that determine the repository format
Repository options - Runtime options for accessing repositories
Config file - Repository-wide settings stored in the repository
Environment variables - Override settings from environment

Repository Initialization

Initialize a New Repository

use rustic_core::{
    Repository, RepositoryOptions, 
    ConfigOptions, KeyOptions, Credentials,
    repofile::MasterKey
};
use rustic_backend::BackendOptions;

let backends = BackendOptions::default()
    .repository("/path/to/repo")
    .to_backends()?;

let repo_opts = RepositoryOptions::default();
let key_opts = KeyOptions::default();
let config_opts = ConfigOptions::default();

let repo = Repository::new(&repo_opts, &backends)?.init(
    &Credentials::password("my-password"),
    &key_opts,
    &config_opts,
)?;

Using a Master Key

Generate and save a master key for keyless access:

use rustic_core::repofile::MasterKey;

// Generate a new master key
let master_key = MasterKey::new();

// IMPORTANT: Save this key securely!
println!("Master key: {}", master_key.to_string());

let repo = Repository::new(&repo_opts, &backends)?.init(
    &Credentials::Masterkey(master_key),
    &key_opts,
    &config_opts,
)?;

Hot/Cold Repository

Initialize a repository with hot and cold storage:

let backends = BackendOptions::default()
    .repository("/cold/storage/repo")  // Cold storage (S3, archive, etc.)
    .repo_hot("/hot/storage/repo")     // Hot storage (local SSD)
    .to_backends()?;

let repo = Repository::new(&repo_opts, &backends)?.init(
    &credentials,
    &key_opts,
    &config_opts,
)?;

Configuration Options

See /home/daytona/workspace/source/crates/core/src/commands/config.rs:119-212

Repository Version

let config_opts = ConfigOptions::default()
    .set_version(Some(2)); // Use repository version 2 (supports compression)

Chunker Configuration

use rustic_core::Chunker;
use bytesize::ByteSize;

let config_opts = ConfigOptions::default()
    .set_chunker(Some(Chunker::Rabin))  // Rabin chunker (default)
    .set_chunk_size(Some(ByteSize::mib(1)))  // Average chunk size: 1 MiB
    .set_chunk_min_size(Some(ByteSize::kib(512)))  // Min chunk: 512 KiB  
    .set_chunk_max_size(Some(ByteSize::mib(8)));  // Max chunk: 8 MiB

// Or use fixed-size chunker
let config_opts = ConfigOptions::default()
    .set_chunker(Some(Chunker::FixedSize))
    .set_chunk_size(Some(ByteSize::mib(1)));

Compression

// Set compression level (v2 repos only)
// Levels: -7 to -1 (fast), 1 to 22 (max compression)
// 0 = no compression
let config_opts = ConfigOptions::default()
    .set_compression(Some(3)); // Balanced compression

// Maximum compression
let config_opts = ConfigOptions::default()
    .set_compression(Some(22));

// Fast compression
let config_opts = ConfigOptions::default()
    .set_compression(Some(-1));

Pack Sizes

use bytesize::ByteSize;

// Configure data pack sizes
let config_opts = ConfigOptions::default()
    .set_datapack_size(Some(ByteSize::mib(32)))  // Default: 32 MiB
    .set_datapack_size_limit(Some(ByteSize::gib(1)))  // Max: 1 GiB
    .set_datapack_growfactor(Some(32));  // Growth factor

// Configure tree pack sizes  
let config_opts = ConfigOptions::default()
    .set_treepack_size(Some(ByteSize::mib(4)))  // Default: 4 MiB
    .set_treepack_size_limit(Some(ByteSize::mib(256)))  // Max: 256 MiB
    .set_treepack_growfactor(Some(32));  // Growth factor

Pack Size Tolerance

// Allow packs to be 30%-130% of target size
let config_opts = ConfigOptions::default()
    .set_min_packsize_tolerate_percent(Some(30))  // Min: 30% of target
    .set_max_packsize_tolerate_percent(Some(130)); // Max: 130% of target

// No upper limit (always tolerate larger packs)
let config_opts = ConfigOptions::default()
    .set_max_packsize_tolerate_percent(Some(0));

Append-Only Mode

// Enable append-only mode (prevents deletion and modification)
let config_opts = ConfigOptions::default()
    .set_append_only(Some(true));

// Note: Once enabled, you cannot run forget, prune, or modify config
// without first disabling append-only mode

Extra Verification

// Enable extra verification (decompress/decrypt before upload)
let config_opts = ConfigOptions::default()
    .set_extra_verify(Some(true));

Modifying Repository Configuration

Change settings on an existing repository:

let mut repo = Repository::new(&repo_opts, &backends)?
    .open(&credentials)?;

// Update configuration
let config_opts = ConfigOptions::default()
    .set_compression(Some(5))
    .set_datapack_size(Some(ByteSize::mib(64)));

let changed = repo.apply_config(&config_opts)?;
if changed {
    println!("Configuration updated");
} else {
    println!("No changes to configuration");
}

Repository Options

See /home/daytona/workspace/source/crates/core/src/repository.rs:88-147 Control how the repository is accessed:

Cache Configuration

use std::path::PathBuf;

// Disable cache
let repo_opts = RepositoryOptions::default()
    .no_cache(true);

// Use custom cache directory
let repo_opts = RepositoryOptions::default()
    .cache_dir(Some(PathBuf::from("/custom/cache")));

Warm-Up Options

Prefetch pack files for faster access:

use rustic_core::CommandInput;
use jiff::SignedDuration;

// Enable automatic warm-up
let repo_opts = RepositoryOptions::default()
    .warm_up(true);

// Use custom warm-up command
let repo_opts = RepositoryOptions::default()
    .warm_up_command(Some(CommandInput::from_str("prefetch.sh %id")?));

// Wait for warm-up completion
let repo_opts = RepositoryOptions::default()
    .warm_up_wait_command(Some(CommandInput::from_str("wait.sh %id")?))
    .warm_up_wait(Some(SignedDuration::from_mins(5)));

// Batch warm-up operations
let repo_opts = RepositoryOptions::default()
    .warm_up_command(Some(CommandInput::from_str("prefetch.sh %ids")?))
    .warm_up_batch(Some(10));  // Process 10 packs at once

Key Management

Add a New Key

use rustic_core::KeyOptions;

// Add a new password-protected key
let key_opts = KeyOptions::default();
let new_key_id = repo.add_key(&Credentials::password("new-password"), &key_opts)?;
println!("Added key: {}", new_key_id);

Key Options

use rustic_core::KeyOptions;

let key_opts = KeyOptions::default()
    .hostname(Some("backup-server".to_string()))
    .username(Some("admin".to_string()));

repo.add_key(&credentials, &key_opts)?;

Environment Variables

rustic_core supports several environment variables:

Cache Settings

# Disable cache
export RUSTIC_NO_CACHE=true

# Custom cache directory
export RUSTIC_CACHE_DIR=/custom/cache

Password

# Set password via environment
export RUSTIC_PASSWORD="my-password"

# Or use password file
export RUSTIC_PASSWORD_FILE=/secure/password.txt

# Or use password command
export RUSTIC_PASSWORD_COMMAND="pass show backup/repo"

Repository Path

# Set repository path
export RUSTIC_REPOSITORY=/path/to/repo

# Or use specific backend
export RUSTIC_REPOSITORY=s3:s3.amazonaws.com/my-bucket/repo

Complete Configuration Example

use rustic_core::*;
use rustic_backend::BackendOptions;
use bytesize::ByteSize;

fn initialize_optimized_repo() -> Result<Repository<Open>, Box<dyn std::error::Error>> {
    // Backend configuration
    let backends = BackendOptions::default()
        .repository("/backup/repo")
        .to_backends()?;
    
    // Repository options (runtime)
    let repo_opts = RepositoryOptions::default()
        .cache_dir(Some(PathBuf::from("/fast/cache")))
        .warm_up(true);
    
    // Configuration options (repository format)
    let config_opts = ConfigOptions::default()
        .set_version(Some(2))  // V2 for compression support
        .set_compression(Some(3))  // Moderate compression
        .set_chunker(Some(Chunker::Rabin))
        .set_chunk_size(Some(ByteSize::mib(1)))
        .set_chunk_min_size(Some(ByteSize::kib(512)))
        .set_chunk_max_size(Some(ByteSize::mib(8)))
        .set_datapack_size(Some(ByteSize::mib(32)))
        .set_datapack_growfactor(Some(32))
        .set_datapack_size_limit(Some(ByteSize::gib(2)))
        .set_treepack_size(Some(ByteSize::mib(4)))
        .set_treepack_growfactor(Some(32))
        .set_min_packsize_tolerate_percent(Some(30))
        .set_max_packsize_tolerate_percent(Some(0))  // No upper limit
        .set_extra_verify(Some(true));  // Extra safety
    
    // Key options
    let key_opts = KeyOptions::default();
    
    // Initialize repository
    let repo = Repository::new(&repo_opts, &backends)?.init(
        &Credentials::password("secure-password"),
        &key_opts,
        &config_opts,
    )?;
    
    Ok(repo)
}

Configuration Best Practices

For Fast Backups

let config_opts = ConfigOptions::default()
    .set_compression(Some(-1))  // Fastest compression
    .set_chunk_size(Some(ByteSize::mib(2)))  // Larger chunks
    .set_datapack_size(Some(ByteSize::mib(64)));  // Larger packs

For Maximum Compression

let config_opts = ConfigOptions::default()
    .set_compression(Some(22))  // Maximum compression
    .set_chunk_size(Some(ByteSize::kib(512)))  // Smaller chunks
    .set_extra_verify(Some(true));  // Verify data

For Large Files

let config_opts = ConfigOptions::default()
    .set_chunk_size(Some(ByteSize::mib(4)))  // Larger average chunk
    .set_chunk_max_size(Some(ByteSize::mib(16)))  // Larger max chunk
    .set_datapack_size(Some(ByteSize::mib(128)));  // Larger packs

For Many Small Files

let config_opts = ConfigOptions::default()
    .set_chunk_size(Some(ByteSize::kib(256)))  // Smaller chunks
    .set_treepack_size(Some(ByteSize::mib(8)))  // Larger tree packs
    .set_datapack_size(Some(ByteSize::mib(16)));  // Smaller data packs

Get Started

Core Concepts

Guides

Examples

Repository Configuration

Repository Configuration

Overview

Repository Initialization

Configuration Options

Repository Version

Chunker Configuration

Compression

Pack Sizes

Pack Size Tolerance

Append-Only Mode

Extra Verification

Modifying Repository Configuration

Repository Options

Cache Configuration

Warm-Up Options

Key Management

Add a New Key

Key Options

Environment Variables

Cache Settings

Password

Repository Path

Complete Configuration Example

Configuration Best Practices

For Fast Backups

For Maximum Compression

For Large Files

For Many Small Files

See Also

Build docs developers (and LLMs) love

Get Started

Core Concepts

Guides

Examples

Documentation Index

​Repository Configuration

​Overview

​Repository Initialization

​Configuration Options

​Repository Version

​Chunker Configuration

​Compression

​Pack Sizes

​Pack Size Tolerance

​Append-Only Mode

​Extra Verification

​Modifying Repository Configuration

​Repository Options

​Cache Configuration

​Warm-Up Options

​Key Management

​Add a New Key

​Key Options

​Environment Variables

​Cache Settings

​Password

​Repository Path

​Complete Configuration Example

​Configuration Best Practices

​For Fast Backups

​For Maximum Compression

​For Large Files

​For Many Small Files

​See Also

Build docs developers (and LLMs) love

Repository Configuration

Overview

Repository Initialization

Configuration Options

Repository Version

Chunker Configuration

Compression

Pack Sizes

Pack Size Tolerance

Append-Only Mode

Extra Verification

Modifying Repository Configuration

Repository Options

Cache Configuration

Warm-Up Options

Key Management

Add a New Key

Key Options

Environment Variables

Cache Settings

Password

Repository Path

Complete Configuration Example

Configuration Best Practices

For Fast Backups

For Maximum Compression

For Large Files

For Many Small Files

See Also