Example lora sync

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Build: cmake --preset linux-ninja-release && cmake --build --preset linux-ninja-release

LoRA Cross-Shard Synchronization Example

This example demonstrates how to use ThemisDB's automatic cross-shard LoRA/adapter synchronization feature.

Overview

The example shows:

• Setting up the sync infrastructure (storage, topology, consistency checker)
• Configuring automatic synchronization with replication
• Creating and syncing LoRA adapters
• Monitoring sync status and metrics
• Handling sync callbacks

Building

cd /home/runner/work/ThemisDB/ThemisDB
mkdir -p build && cd build
cmake .. -DTHEMIS_BUILD_TESTS=ON -DTHEMIS_ENABLE_LORA_TESTS=ON
cmake --build . --target example_lora_sync

Running

./example_lora_sync

Expected Output

=== ThemisDB LoRA Cross-Shard Synchronization Example ===

1. Creating LoRA Storage Service...
✓ Storage service created

2. Setting up Shard Topology...
  Added shard_1 (dc1)
  Added shard_2 (dc1)
  Added shard_3 (dc1)
  Added shard_4 (dc2)
  Added shard_5 (dc2)
✓ Topology configured with 5 shards

3. Creating Consistency Checker...
✓ Consistency checker created

4. Creating Sync Manager...
✓ Sync manager created
  Sync interval: 60s
  Replication factor: 3

5. Registering sync callback...
✓ Callback registered

6. Creating example adapters...
  ✓ Created adapter_1
  ✓ Created adapter_2
  ✓ Created adapter_3

7. Performing manual sync...
✓ Manual sync completed
  Checked: 3
  Synced: 3
  Failed: 0

8. Checking sync status...
  adapter_1:
    Synced: yes
    Version: 1
    Failures: 0
  adapter_2:
    Synced: yes
    Version: 1
    Failures: 0
  adapter_3:
    Synced: yes
    Version: 1
    Failures: 0

9. Viewing statistics...
  Total syncs: 1
  Successful: 3
  Failures: 0
  Bytes transferred: 3072
  Adapters tracked: 3

10. Starting automatic sync...
✓ Auto-sync is running
  Will sync every 60 seconds

Waiting 5 seconds...

11. Cleaning up...
✓ Sync manager stopped

=== Example completed successfully ===

Key Components

1. Storage Service

Manages persistent storage of LoRA adapters with versioning and encryption support.

2. Shard Topology

Maintains cluster topology information including shard locations, health status, and datacenter awareness.

3. Consistency Checker

Validates adapter integrity using checksums and digital signatures, and resolves version conflicts.

4. Sync Manager

Orchestrates automatic synchronization across shards with configurable replication factor and retry logic.

Configuration Options

Replication Factor

Controls how many replica shards each adapter is synced to:

sync_config.replication_factor = 3;  // 3-way replication

Sync Interval

Controls how often auto-sync runs:

sync_config.sync_interval = std::chrono::seconds(300);  // 5 minutes

Conflict Resolution

Choose how version conflicts are resolved:

sync_config.conflict_resolution = "newest_wins";  // or "manual"

Performance

Control concurrent operations and rate limiting:

sync_config.max_concurrent_syncs = 4;
sync_config.max_transfer_rate_mbps = 100;

Integration with RAID

The sync manager works seamlessly with ThemisDB's RAID configurations:

• RAID 1 (MIRROR): Full N-way replication for high availability
• RAID 5 (PARITY): Erasure coding for storage efficiency
• RAID 10: Striped mirrors for performance + reliability

Set the replication factor to match your RAID configuration.

Monitoring

Status API

Check sync status for individual adapters:

auto status = sync_manager->getSyncStatus("adapter_1");
std::cout << "Synced: " << status.is_synced << std::endl;
std::cout << "Version: " << status.local_version << std::endl;

Statistics API

Get aggregate statistics:

auto stats = sync_manager->getStats();
std::cout << "Total syncs: " << stats["total_syncs"] << std::endl;
std::cout << "Failures: " << stats["sync_failures"] << std::endl;

Prometheus Metrics

If built with Prometheus support, metrics are automatically exported:

• themis_lora_sync_syncs_total - Total sync operations
• themis_lora_sync_syncs_success_total - Successful syncs
• themis_lora_sync_syncs_failures_total - Failed syncs
• themis_lora_sync_bytes_transferred_total - Bytes transferred
• themis_lora_sync_sync_duration_seconds - Sync duration histogram
• themis_lora_sync_adapters_tracked - Number of adapters tracked
• themis_lora_sync_replication_lag_seconds - Replication lag gauge

See Also

• Cross-Shard Sync Documentation
• RAID Implementation Report
• LoRA Storage Testing Guide

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