claude-mcp-demo/claude-nfs-benchmark.md

NFS Performance Benchmark - Claude Analysis

Date: 2026-01-19
Storage Class: nfs-csi
NFS Server: 192.168.0.105:/nfs/NFS/ocp
Test Environment: OpenShift Container Platform (OCP)
Tool: fio (Flexible I/O Tester)

Executive Summary

Performance testing of the NAS storage via nfs-csi storage class reveals actual throughput of 65-80 MiB/s for sequential operations. This represents typical performance for 1 Gbps Ethernet NFS configurations.

Test Configuration

NFS Mount Options

• rsize/wsize: 1048576 (1MB) - optimal for large sequential transfers
• Protocol options: hard, noresvport
• Timeout: 600 seconds
• Retrans: 2

Test Constraints

• CPU: 500m
• Memory: 512Mi
• Namespace: nfs-benchmark (ephemeral)
• PVC Size: 5Gi

Benchmark Results

Sequential I/O (1M block size)

Sequential Write

• Throughput: 70.2 MiB/s (73.6 MB/s)
• IOPS: 70
• Test Duration: 31 seconds
• Data Written: 2176 MiB

Latency Distribution:

• Median: 49 µs
• 95th percentile: 75 µs
• 99th percentile: 212 ms (indicating occasional network delays)

Sequential Read

• Throughput: 80.7 MiB/s (84.6 MB/s)
• IOPS: 80
• Test Duration: 20 seconds
• Data Read: 1615 MiB

Latency Distribution:

• Median: 9 ms
• 95th percentile: 15 ms
• 99th percentile: 150 ms

Synchronized Write Test

Purpose: Measure actual NAS performance without local caching

• Throughput: 65.9 MiB/s (69.1 MB/s)
• IOPS: 65
• fsync latency: 13-15ms average

This test provides the most realistic view of actual NAS write performance, as each write operation is synchronized to disk before returning.

Random I/O (4K block size, cached)

Note: These results heavily leverage local page cache and do not represent actual NAS performance.

Random Write

• Throughput: 1205 MiB/s (cached)
• IOPS: 308k (cached)

Random Read

• Throughput: 1116 MiB/s (cached)
• IOPS: 286k (cached)

Mixed Workload (70% read / 30% write, 4 concurrent jobs)

• Read Throughput: 426 MiB/s
• Read IOPS: 109k
• Write Throughput: 183 MiB/s
• Write IOPS: 46.8k

Note: High IOPS values indicate substantial local caching effects.

Analysis

Performance Characteristics

1. Actual NAS Bandwidth: ~65-80 MiB/s

   • Consistent across sequential read/write tests
   • Synchronized writes confirm this range

2. Network Bottleneck Indicators:

   • Performance aligns with 1 Gbps Ethernet (theoretical max ~125 MiB/s)
   • Protocol overhead and network latency account for 40-50% overhead
   • fsync operations show 13-15ms latency, indicating network RTT

3. Caching Effects:

   • Random I/O tests show 10-15x higher throughput due to local page cache
   • Not representative of actual NAS capabilities
   • Useful for understanding application behavior with cached data

Bottleneck Analysis

The ~70 MiB/s throughput is likely limited by:

1. Network Bandwidth (Primary)

   • 1 Gbps link = ~125 MiB/s theoretical maximum
   • NFS protocol overhead reduces effective throughput to 55-60%
   • Observed performance matches expected 1 Gbps NFS behavior

2. Network Latency

   • fsync showing 13-15ms indicates network + storage latency
   • Each synchronous operation requires full round-trip

3. NAS Backend Storage (Unknown)

   • Current tests cannot isolate NAS disk performance
   • Backend may be faster than network allows

Recommendations

Immediate Improvements

1. Upgrade to 10 Gbps Networking

   • Most cost-effective improvement
   • Could provide 8-10x throughput increase
   • Requires network infrastructure upgrade

2. Enable NFS Multichannel (if supported)

   • Use multiple network paths simultaneously
   • Requires NFS 4.1+ with pNFS support

Workload Optimization

1. For Write-Heavy Workloads:

   • Consider async writes (with data safety trade-offs)
   • Batch operations where possible
   • Use larger block sizes (already optimized at 1MB)

2. For Read-Heavy Workloads:

   • Current performance is acceptable
   • Application-level caching will help significantly
   • Consider ReadOnlyMany volumes for shared data

Alternative Solutions

1. Local NVMe Storage (for performance-critical workloads)

   • Use local-nvme-retain storage class for high-IOPS workloads
   • Reserve NFS for persistent data and backups

2. Tiered Storage Strategy

   • Hot data: Local NVMe
   • Warm data: NFS
   • Cold data: Object storage (e.g., MinIO)

Conclusion

The NAS is performing as expected for a 1 Gbps NFS configuration, delivering consistent 65-80 MiB/s throughput. The primary limitation is network bandwidth, not NAS capability. Applications with streaming I/O patterns will benefit from the current configuration, while IOPS-intensive workloads should consider local storage options.

For significant performance improvements, upgrading to 10 Gbps networking is the most practical path forward.

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Test Methodology

All tests were conducted using:

• Ephemeral namespace with automatic cleanup
• Constrained resources (500m CPU, 512Mi memory)
• fio version 3.6
• Direct I/O where applicable to minimize caching effects

Benchmark pod and resources were automatically cleaned up after testing, following ephemeral testing protocols.