From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 29 Aug 2017 10:30:42 +0200 From: Christoph Hellwig To: Guan Junxiong Cc: Christoph Hellwig , Jens Axboe , Keith Busch , linux-block@vger.kernel.org, Sagi Grimberg , linux-nvme@lists.infradead.org, "Shenhong (C)" , niuhaoxin , Lilangbo Subject: Re: [PATCH 07/10] nvme: track shared namespaces Message-ID: <20170829083042.GC10487@lst.de> References: <20170823175815.3646-1-hch@lst.de> <20170823175815.3646-8-hch@lst.de> <20170828143011.GA29260@lst.de> <33a56620-f615-71b0-9321-bde8494132db@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <33a56620-f615-71b0-9321-bde8494132db@huawei.com> List-ID: On Tue, Aug 29, 2017 at 10:42:18AM +0800, Guan Junxiong wrote: > As for the __nvme_find_ns_head function, can it lookup the namespace > globally, not in the current subsytem. No. > Take hypermetro scenario for Please define "hypermetro" > example, two namespaces which should be viewed as the same namespaces > from the database application but exist in two different cities respectively. > Some vendors maybe specify those two namespaces with the same UUID. Then these vendors are non-compliant IFF the controllers don't belong to the same subsystem. > In addition, could you add a switch to turn on/off finding namespaces in > a subsystem-wide level or globally? No. > Can namespace be shared between two subsystem? No - if you share namespace access you are in the same subsystem. From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@lst.de (Christoph Hellwig) Date: Tue, 29 Aug 2017 10:30:42 +0200 Subject: [PATCH 07/10] nvme: track shared namespaces In-Reply-To: <33a56620-f615-71b0-9321-bde8494132db@huawei.com> References: <20170823175815.3646-1-hch@lst.de> <20170823175815.3646-8-hch@lst.de> <20170828143011.GA29260@lst.de> <33a56620-f615-71b0-9321-bde8494132db@huawei.com> Message-ID: <20170829083042.GC10487@lst.de> On Tue, Aug 29, 2017@10:42:18AM +0800, Guan Junxiong wrote: > As for the __nvme_find_ns_head function, can it lookup the namespace > globally, not in the current subsytem. No. > Take hypermetro scenario for Please define "hypermetro" > example, two namespaces which should be viewed as the same namespaces > from the database application but exist in two different cities respectively. > Some vendors maybe specify those two namespaces with the same UUID. Then these vendors are non-compliant IFF the controllers don't belong to the same subsystem. > In addition, could you add a switch to turn on/off finding namespaces in > a subsystem-wide level or globally? No. > Can namespace be shared between two subsystem? No - if you share namespace access you are in the same subsystem.