On Mon, Sep 18, 2017 at 04:14:53PM -0700, Christoph Hellwig wrote:
> This patch adds initial multipath support to the nvme driver. For each
> namespace we create a new block device node, which can be used to access
> that namespace through any of the controllers that refer to it.
>
> Currently we will always send I/O to the first available path, this will
> be changed once the NVMe Asynchronous Namespace Access (ANA) TP is
> ratified and implemented, at which point we will look at the ANA state
> for each namespace. Another possibility that was prototyped is to
> use the path that is closes to the submitting NUMA code, which will be
> mostly interesting for PCI, but might also be useful for RDMA or FC
> transports in the future. There is not plan to implement round robin
no ^
> or I/O service time path selectors, as those are not scalable with
> the performance rates provided by NVMe.
>
> The multipath device will go away once all paths to it disappear,
> any delay to keep it alive needs to be implemented at the controller
> level.
Sorry for the typo only mail, I'll be going around a real review soon but I
wanted to test the patchset in my nvme-rdma setup and just hit a panic in
ib_core with your branched merged into -rc1.
Byte,
Johannes
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