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New Member

Two Fabric redundancy and storage flapping


I have a fairly new Nexus 5548 implementation, using the Nexus for stricly storage. I have two 5548s for two different Fabrics, for redundancy. They are two seperate fabrics, and the Nexus are not stacked so they are managed individually. When I have both Nexus online my VMware side starts flapping, and loosing storage which causes my ESXi hosts to lock up and VMs to go unresponsive. This does not happen 100% of the time, but it happens intermitentaly and sometimes is catestrophic to datacenter services. When I shut down one of the Nexus switches, storage comes back and everything is healthy.

All hosts are connected via 4GB FC (supposedly HP cant do 8GB without problems)

5/6 of my hosts are on HP c7000 enclosures via 10gb FlexFabric switches, the rest via UCS

Netapp clustered pair is the target. When the ESXi hosts loose storage, they are still flogi'd in to the storage and fabric

ESXi 5.0 w/newest (and correct) drivers. VMWare tech support sees no problems, other than the "storage is getting pulled from the host"

Newest firmware on everything HP & UCS

Nexus running 5.0(3)N2(2a)

Using per-iniator zoning

Fabric-A and Fabric-B are different VSANs

Any ideas? Do I have a design flaw in my fabric? HP, Cisco, Netapp, and VMware all pretty much have no clue. So this forum is a shot in the dark. Thanks for ANY ideas you guys can provide

Cisco Employee

Two Fabric redundancy and storage flapping


Do you see anything in the logs at the time of the event on the switches? Show logging log?

New Member

Two Fabric redundancy and storage flapping


I have looked at that extensively and unfortunately I dont see anything there, which kinda leaves me at a dead end.


Two Fabric redundancy and storage flapping

could it be some kind of trespassing on the storage array ? LUNs start balancing between the controllers and eventually the host times out. Have you tried different failover (NMP) policy in ESXi ?

New Member

Two Fabric redundancy and storage flapping


What is the FC port speed set on nexus 5548.


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