NVMe/TCP vs iSCSI: Which Protocol is Right for Your Infrastructure?
A detailed comparison between NVMe/TCP and iSCSI protocols to help you make an informed decision for your storage infrastructure.
Introduction
As organizations modernize their storage infrastructure, choosing between NVMe/TCP and iSCSI becomes a critical decision. This comprehensive comparison will help you understand the key differences and make an informed choice.
Protocol Overview
NVMe/TCP
- Purpose-built for flash storage
- Simplified command set
- Parallel command processing
- Deep queue support
iSCSI
- Legacy SCSI protocol
- Sequential processing
- Limited queue depth
- Higher protocol overhead
Performance Comparison
The performance differences between NVMe/TCP and iSCSI are significant and can impact various aspects of your storage operations.
Latency Analysis
NVMe/TCP Latency
25-40µs typical latency
iSCSI Latency
100-200µs typical latency
IOPS and Throughput
| Metric | NVMe/TCP | iSCSI |
|---|---|---|
| Max IOPS | 1.5M | 400K |
| Throughput | 40GB/s | 10GB/s |
| Queue Depth | 64K | 128 |
Implementation Differences
Protocol Stack
NVMe/TCP features a streamlined protocol stack specifically designed for flash storage, while iSCSI carries the overhead of translating SCSI commands.
Command Processing
NVMe/TCP processes commands in parallel with multiple queues, while iSCSI processes commands sequentially through a single queue.
Cost Analysis
Infrastructure Costs
- Hardware Requirements: Both protocols work with standard NICs
- Software Licensing: Similar costs for both protocols
- Training: Lower training costs for NVMe/TCP due to simpler protocol
Migration Considerations
Migration Path
- Phased Approach: Gradually migrate workloads from iSCSI to NVMe/TCP
- Coexistence: Both protocols can run simultaneously on the same network
- Testing: Validate performance improvements before full migration
Conclusion
NVMe/TCP offers significant performance advantages over iSCSI, particularly for modern flash storage arrays and high-performance workloads. While iSCSI remains viable for legacy systems, NVMe/TCP is the clear choice for new deployments and infrastructure modernization projects.