From mboxrd@z Thu Jan 1 00:00:00 1970 From: loberman@redhat.com (Laurence Oberman) Date: Fri, 16 Nov 2018 14:34:26 -0500 Subject: nvme: allow ANA support to be independent of native multipathing In-Reply-To: <20181116192802.GA30057@redhat.com> References: <20181114053837.GA15086@redhat.com> <30cf7af7-8826-55bd-e39a-4f81ed032f6d@suse.de> <20181114174746.GA18526@redhat.com> <87c931e5-4ac9-1795-8d40-cc5541d3ebcf@suse.de> <20181115174605.GA19782@redhat.com> <20181116091458.GA17267@lst.de> <37098edd-4dea-b58f-bca6-3be9af8ec4ee@suse.de> <20181116094947.GA19296@lst.de> <20181116101752.GA21531@lst.de> <20181116192802.GA30057@redhat.com> Message-ID: <1542396866.13202.0.camel@redhat.com> On Fri, 2018-11-16@14:28 -0500, Mike Snitzer wrote: > On Fri, Nov 16 2018 at??5:17am -0500, > Christoph Hellwig wrote: > > > On Fri, Nov 16, 2018@11:06:32AM +0100, Hannes Reinecke wrote: > > > Ok, so would you be happy with making ANA support configurable? > > > > I've looked a bit over the whole situation, and what I think we > > need > > to do is: > > > > ?a) warn if we see a ANA capable device without multipath support > > ????so people know it is not going to work properly. > > I disagree with your cynicism but v2 of this patch now emits a > warning > accordingly. > > > ?b) deprecate the multipath module option.??It was only intended as > > ????a migration for any pre-existing PCIe multipath user if there > > ????were any, not to support any new functionality.??So for 4.20 > > ????put in a patch that prints a clear warning when it is used, > > ????including a link to the nvme list, and then for 4.25 or so > > ????remove it entirely unless something unexpected come up. > > You rejected the idea of allowing fine-grained control over whether > native NVMe multipathing is enabled or not on a per-namespace basis. > All we have is the coarse-grained nvme_core.multipath=N knob.??Now > you're forecasting removing even that.??Please don't do that. > > > This whole drama of optional multipath use has wasted way too much > > of everyones time already. > > It has wasted _way_ too much time. > > But the drama is born out of you rejecting that we need to preserve > multipath-tools and dm-multipath's ability to work across any > transport.??You don't need to do that work: Hannes, myself and others > have always been willing and able -- if you'd let us. > > IIRC it was at 2016's LSF in Boston where Ewan Milne and I had a > face-to-face conversation with you in the hallway track where you > agreed > that ANA support would be activated if the capability was advertised > by > the target.??The model we discussed is that it would be comparable to > how ALUA gets enabled during SCSI LUN discovery. > > I hope you can see your way forward to be more accommodating now. > Especially given the proposed changes are backed by NVMe standards. > > Please, PLEASE take v2 of this patch.. please? ;) > > Thanks, > Mike I am begging you take it too please Thanks Laurence