Messages in this thread | | | Subject | Re: [PATCH v6 00/16] nvmet: add target passthru commands support | From | Sagi Grimberg <> | Date | Mon, 29 Jul 2019 09:15:06 -0700 |
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>> This is different from multipath on say a multi-controller PCI device >> and trying to expose both those controllers through passthru. this is >> where the problems we are discussing come up. > > I *think* there is some confusion. I *think* Sagi is talking about network multi-path (i.e. the ability for the host to connect to a controller on the target via two different network paths that fail-over as needed). I *think* Logan is talking about multi-port PCIe NVMe devices that allow namespaces to be accessed via more than one controller over PCIe (dual-port NVMe SSDs being the most obvious example of this today).
Yes, I was referring to fabrics multipathing which is somewhat orthogonal to the backend pci multipathing (unless I'm missing something).
>> But it's the multipath through different ports that >> seems important for fabrics. ie. If I have a host with a path through >> RDMA and a path through TCP they should both work and allow fail over. > > Yes, or even two paths that are both RDMA or both TCP but which take a different path through the network from host to target. > >> Our real-world use case is to support our PCI device which has a bunch >> of vendor unique commands and isn't likely to support multiple >> controllers in the foreseeable future. > > I think solving passthru for single-port PCIe controllers would be a good start.
Me too.
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