Understanding the supported erasure coding configurations is crucial for planning MinIO deployments, as it affects storage efficiency, fault tolerance, and performance characteristics.
This is particularly important for:
- Capacity planning and storage efficiency
- Fault tolerance requirements
- Performance optimization
- Hardware procurement decisions
- Object size optimization
Answer
MinIO supports a wide range of erasure coding configurations with the following constraints:
Supported Configurations
General Rules:
- Any K+M combination where 2 ≤ K+M ≤ 16
- Parity constraint: 0 ≤ M < K
- K = data drives, M = parity drives
Common Production Configurations
Most Popular:
-
EC 12+4 (75% usable capacity)
- 12 data drives + 4 parity drives = 16 total
- Can survive up to 4 concurrent drive failures
- Excellent storage efficiency
-
EC 5+3 (62.5% usable capacity)
- 5 data drives + 3 parity drives = 8 total
- Can survive up to 3 concurrent drive/node failures
- Good balance of efficiency and fault tolerance
Configuration Guidelines
Avoid K=M configurations (not recommended):
- Examples: 4+4, 6+6, 8+8
- Risk: Losing M drives with surviving K=M drives can cause a split brain situation
- MinIO prefers to avoid this scenario for data safety
Object Size Considerations
Small Objects:
- Higher K+M configurations have more metadata overhead per object
- Each object requires metadata across all K+M drives
- Consider lower K+M for workloads with many small files
Large Objects:
- Benefit from higher K+M configurations due to better parallelism
- Metadata overhead becomes negligible relative to object size
- Better performance with more drives involved in I/O operations
Performance Impact:
- More drives (higher K+M) = better throughput for large objects
- Fewer drives (lower K+M) = lower latency for small objects
- Network bandwidth utilization scales with drive count
Examples of Valid Configurations
| Configuration | Total Drives | Efficiency | Max Failures | Best For |
|---|---|---|---|---|
| EC 4+2 | 6 | 66.7% | 2 | Small objects, limited hardware |
| EC 6+2 | 8 | 75% | 2 | Mixed workloads |
| EC 8+3 | 11 | 72.7% | 3 | Large objects, high availability |
| EC 8+4 | 12 | 66.7% | 4 | Critical data, large objects |
| EC 12+4 | 16 | 75% | 4 | Large objects, maximum performance |
Selection Considerations
- Storage Efficiency: Higher K/M ratio = better efficiency
- Fault Tolerance: Higher M = more drive failures tolerated
- Performance: More drives generally = better performance for large objects
- Object Size Profile: Match configuration to typical object sizes
- Hardware Constraints: Must match available drive slots
- Network Topology: Consider rack/node distribution for node failures
Replication vs Erasure Coding
- Replication: Simple 2x or 3x copies (50% or 33% efficiency)
- Erasure Coding: Mathematical redundancy (much higher efficiency)
- MinIO recommends erasure coding for production deployments