Storage Networking: Fibre Channel, iSCSI, and NVMe-oF
Networking items reward precision about zoning, addressing, and multipathing across the three block transports PowerStore supports.
Fibre Channel
- PowerStore offers 32 Gb FC modules and supports FC-NVMe on the same class of hardware.
- Zone single-initiator, single-target: one host WWPN paired with one array port WWPN per zone, so multipathing owns failover rather than the fabric.
- Register host WWPNs as host initiators before mapping; an unlogged host cannot be validated.
- For FC-NVMe the host registers an NQN and consumes NVMe namespaces, but the zoning discipline is unchanged.
iSCSI
- Use dedicated VLANs, and jumbo frames (MTU 9000) only where every hop supports it: host NIC, switch, and array port.
- Do not bond or LACP the array's iSCSI ports toward a host; use MPIO with one portal per node so failover works.
- Enable flow control on the storage VLAN and confirm the host sees one session per portal.
- CHAP can be one-way (array authenticates the host) or mutual; the secret must match on both sides and be re-checked after any host rebuild.
NVMe-oF
- NVMe/TCP runs on 25 GbE ports in later PowerStoreOS releases; NVMe/FC uses the FC modules. Hosts register an NQN and discover the array through a discovery controller before logging in to a subsystem.
Worked example
A Linux host has two HBAs and the array presents two FC ports per node. Reasoning: build four zones, host HBA1 to node A port 1 and node B port 1, then HBA2 to node A port 2 and node B port 2. The host should show four paths, two active-optimized per node. Fewer paths means a cabling, zoning, or multipath problem, not an array fault, so fix the fabric before opening a support case.
Traps
- Zoning switch-port to switch-port instead of WWPN to WWPN.
- Mixing a jumbo-frame host with 1500-byte array ports, producing silent retransmits and latency.
- Sharing a subnet between host iSCSI traffic and array management.
- Assigning the same initiator to two hosts, splitting access unpredictably.
- Forgetting to reapply CHAP on one side after a host rebuild.