---
title: "Storage Engine"
---

# Storage Engine

High-performance LSM-tree based storage with intelligent compaction and tiering.

## Overview

HeliosDB's storage engine is built on an optimized LSM-tree architecture with:
- Intelligent compaction strategies
- Hot/warm/cold data tiering
- Columnar storage optimization
- Hardware-accelerated compression

## Quick Start

```sql
-- Configure storage tier
ALTER TABLE logs SET STORAGE TIER 'cold'
  WITH (compression = 'zstd', compression_level = 9);

-- Set compaction strategy
ALTER TABLE events SET COMPACTION STRATEGY 'leveled'
  WITH (level_size_ratio = 10, max_bytes_for_level_base = '256MB');

-- Monitor storage usage
SELECT * FROM helios_storage_stats;
```

## Key Features

| Feature | Description |
|---------|-------------|
| **LSM-Tree** | Write-optimized with configurable compaction |
| **Tiered Storage** | Hot, warm, cold data management |
| **Compression** | LZ4, Zstd, Snappy with level tuning |
| **Columnar** | Column-oriented storage for analytics |
| **Bloom Filters** | Fast negative lookups |

## Documentation

| Document | Description |
|----------|-------------|
| [LSM_TUNING_GUIDE.md](https://www.heliosdb.com/docs/full/features/storage/lsm_tuning_guide/) | LSM-tree configuration |
| [COMPACTION_STRATEGY_GUIDE.md](https://www.heliosdb.com/docs/full/features/storage/compaction_strategy_guide/) | Compaction strategies |

## Related

- **Performance Tuning**: `/docs/guides/user/PERFORMANCE_TUNING_GUIDE.md`
- **Backup & Recovery**: `/docs/guides/user/BACKUP_RECOVERY_GUIDE.md`

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