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Storage Tiers in VergeOS vSAN#

Overview#

VergeOS vSAN implements a sophisticated storage tiering system that balances performance, capacity, and cost. The system supports up to 6 tiers (0-5), each optimized for different workloads and data types. This tiered architecture allows organizations to efficiently manage their storage resources by placing data on the most appropriate tier based on performance requirements and access patterns.

For vSAN sizing recommendations, see the Node Sizing Guide.

Tier Specifications#

Tier 0: Metadata Tier#

  • Hardware: High-endurance NVMe-based SSD
  • Purpose: Used exclusively for vSAN metadata
  • Characteristics: Optimized for ultra-low latency operations
  • Use Case: System metadata management

Tier 1: High-Performance Tier#

  • Hardware: High-endurance NVMe-based SSDs
  • Purpose: Write-intensive workloads
  • Characteristics: Maximum I/O performance, high durability
  • Use Cases:
    • High-performance databases
    • Heavily used transaction logs
    • Write-intensive applications

Tier 2: Mixed Workload Tier#

  • Hardware: Mid-range SSDs
  • Purpose: Balanced read/write workloads
  • Characteristics: Good balance of performance and cost
  • Use Cases:
    • General-purpose VM storage
    • Mixed application workloads
    • Development environments

Tier 3: Read-Optimized Tier#

  • Hardware: Read-optimized SSDs
  • Purpose: Read-intensive workloads
  • Characteristics: Optimized for read operations
  • Use Cases:
    • Content delivery
    • Application repositories
    • Reference data

Tier 4: Capacity Tier#

  • Hardware: High-capacity HDDs
  • Purpose: Less frequently accessed data
  • Characteristics: High capacity, cost-effective
  • Use Cases:
    • File servers
    • Backup targets
    • Infrequently accessed data

Tier 5: Archive Tier#

  • Hardware: Archival-grade HDDs
  • Purpose: Cold storage and long-term retention
  • Characteristics: Maximum capacity, lowest cost per TB
  • Use Cases:
    • Long-term data retention
    • Compliance archives
    • Backup archives

Implementation Details#

Cross-Node Distribution#

  • Each storage tier spans multiple nodes in the cluster
  • Provides balanced performance across infrastructure
  • Enhances data availability and fault tolerance
  • Enables efficient resource utilization

Performance Optimization#

  • Inline deduplication operates across all tiers
  • Each tier can be independently scaled
  • Automatic load balancing within tiers
  • Intelligent data distribution using hash-based algorithms

Best Practices#

Tier Selection#

  1. Identify workload characteristics:

    • Write intensity
    • Read patterns
    • Performance requirements
    • Capacity needs

  2. Consider cost-performance balance:

    • Match tier capabilities to workload requirements
    • Balance performance needs with budget constraints
    • Account for future growth

  3. Plan capacity carefully:

    • Maintain adequate free space in each tier
    • Consider deduplication ratios
    • Plan for workload growth

Configuration Recommendations#

  1. Metadata Tier (Tier 0):

    • Allocate sufficient space for metadata growth
    • Use highest-endurance NVMe drives available
    • Maintain at least 10% free space

  2. Performance Tiers (Tier 1-3):

    • Size according to active dataset
    • Consider write endurance requirements
    • Balance capacity across nodes

  3. Capacity Tiers (Tier 4-5):

    • Plan for long-term growth
    • Consider backup and archive requirements
    • Implement appropriate retention policies

Monitoring and Management#

Key Metrics to Monitor#

  • Capacity utilization per tier
  • I/O performance metrics
  • Deduplication ratios
  • Error rates and health status

Management Tasks#

  • Regular capacity review
  • Performance optimization
  • Health monitoring
  • Tier balancing

Scaling Considerations#

Vertical Scaling (Scaling Up)#

  • Add capacity to existing tiers
  • Upgrade to faster storage devices
  • Increase cache sizes

Horizontal Scaling (Scaling Out)#

  • Add new nodes to expand tier capacity
  • Maintain balanced distribution
  • Consider performance impact

Troubleshooting#

Common Issues#

  1. Performance Degradation

    • Check tier utilization
    • Verify workload placement
    • Monitor I/O patterns

  2. Capacity Issues

    • Review deduplication ratios
    • Check space allocation
    • Verify tier distribution

  3. Hardware Failures

    • Monitor drive health
    • Check error logs
    • Verify redundancy

Resolution Steps#

  • Identify affected tier and workload
  • Check system logs and metrics
  • Verify hardware health
  • Review configuration settings
  • Apply corrective actions

Integration with Other Features#

Snapshots and Clones#

  • Tier-aware snapshot creation
  • Efficient clone management
  • Space-efficient operations

Replication#

  • Tier-aware replication
  • Bandwidth optimization
  • Consistent data protection