Architecture Overview
Key Design Principles:
- Dual switches for network redundancy
- Minimum 2 NICs per host for multipath
- Dual controller array for storage HA
- dm-multipath aggregates all paths into single device
Storage Network Topology (iSCSI)
Recommended iSCSI Network Architecture
Key Design Principles
Redundancy at Every Level
- Dual NICs: Separate physical ports for each storage path
- Dual Switches: Eliminate single point of failure in network
- Dual Controllers: Active-active storage controllers
Network Isolation
- Dedicated VLAN: Storage traffic isolated from management/VM traffic
- Jumbo Frames: MTU 9000 for optimal performance
- No Routing: Layer 2 connectivity between hosts and storage
iSCSI Path Flow
Physical Cabling
| Component | Connection | Purpose |
|---|---|---|
| NIC Port 1 | Switch 1 | Primary iSCSI path |
| NIC Port 2 | Switch 2 | Secondary iSCSI path |
| Storage CT0 | Both Switches | Controller 0 connectivity |
| Storage CT1 | Both Switches | Controller 1 connectivity |
Network Configuration Summary
| Parameter | Recommendation |
|---|---|
| MTU | 9000 (jumbo frames) |
| VLAN | Dedicated storage VLAN |
| Flow Control | Enabled (send/receive) |
| Speed | 10/25/100 GbE |
| Duplex | Full |
iSCSI Multipath Diagrams
Diagrams specific to iSCSI with dm-multipath.
iSCSI Path Redundancy Model
dm-multipath Architecture
ALUA Path States
Key dm-multipath Settings
| Setting | Recommended Value | Purpose |
|---|---|---|
| no_path_retry | 0 | Fail immediately when all paths down |
| path_selector | service-time 0 | Route based on path latency |
| failback | immediate | Return to optimal path when available |
| path_checker | tur | Test Unit Ready health check |