Re: [SPDK] Namespace sharing between multiple controller

Re: [SPDK] Namespace sharing between multiple controller

[Walker, Benjamin]

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On Wed, 2017-03-08 at 23:42 +0530, Ankur Srivastava wrote:
> Hi All,
> 
> I am using null block devices on my Target side and here is my conf
> file snap (app/nvmf_tgt/nvmf_tgt -c etc/spdk/nvmf.conf.in)
> 
> [Subsystem1]
>   NQN nqn.2016-06.io.spdk:cnode1
>   Core 0
>   Mode Virtual
>   Listen RDMA 192.168.25.3:4420
>   SN SPDK00000000000001
>   Namespace Malloc0
> 
> [Subsystem2]
>   NQN nqn.2016-06.io.spdk:cnode2
>   Core 1
>   Mode Virtual
>   Listen RDMA 192.168.25.31:4420
>   SN SPDK00000000000001
>   Namespace Malloc1
> 
> 
> How can I create multiple controllers and how can I share namespace
> like(Malloc0, Malloc1) between different controllers ??

A new controller will be created each time a new NVMe-oF host
(initiator) connects to a subsystem. That controller will be able to
see all of the namespaces within a subsystem. Note that we don't
currently have emulation for NVMe reservations, so coordination will
need to be done by the clients.

So if you want to have a subsystem with two shared namespaces and two
clients connected, just write:

[Subsystem1]
  NQN nqn.2016-06.io.spdk:cnode1
  Core 0
  Mode Virtual
  Listen RDMA 192.168.25.3:4420
  SN SPDK0000000000001
  Namespace Malloc0
  Namespace Malloc1

Start up the target with that config and then connect two clients to
the same subsystem. They'll each see their own controller but share
namespaces.

The best way to think about NVMe controllers in NVMe-oF is that they're
just sessions in the networking sense of the word. We even call them
spdk_nvmf_session in our code, as opposed to spdk_nvmf_controller. This
isn't an implementation choice that SPDK is making either - that's
really the intended meaning of a controller in the NVMe-oF
specification which sometimes refers to them as "controller sessions".

> 
> 
> Regards
> Ankur
> _______________________________________________
> SPDK mailing list
> SPDK(a)lists.01.org
> https://lists.01.org/mailman/listinfo/spdk

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Re: [SPDK] Namespace sharing between multiple controller

[Ankur Srivastava]

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Thanks a lot, it worked!

One more question

For virtual NVMe Controller ie for null block device at the Targets side,
is it possible to create/delete and specially attach/detach namespaces from
the Initiator side
after connection has been established.

I am using Kernel Initiator (SPDK Target)  so asking in context of nvme cli.



Thanks & Regards
Ankur

On Thu, Mar 9, 2017 at 12:00 AM, Walker, Benjamin <benjamin.walker(a)intel.com
> wrote:

> On Wed, 2017-03-08 at 23:42 +0530, Ankur Srivastava wrote:
> > Hi All,
> >
> > I am using null block devices on my Target side and here is my conf
> > file snap (app/nvmf_tgt/nvmf_tgt -c etc/spdk/nvmf.conf.in)
> >
> > [Subsystem1]
> >   NQN nqn.2016-06.io.spdk:cnode1
> >   Core 0
> >   Mode Virtual
> >   Listen RDMA 192.168.25.3:4420
> >   SN SPDK00000000000001
> >   Namespace Malloc0
> >
> > [Subsystem2]
> >   NQN nqn.2016-06.io.spdk:cnode2
> >   Core 1
> >   Mode Virtual
> >   Listen RDMA 192.168.25.31:4420
> >   SN SPDK00000000000001
> >   Namespace Malloc1
> >
> >
> > How can I create multiple controllers and how can I share namespace
> > like(Malloc0, Malloc1) between different controllers ??
>
> A new controller will be created each time a new NVMe-oF host
> (initiator) connects to a subsystem. That controller will be able to
> see all of the namespaces within a subsystem. Note that we don't
> currently have emulation for NVMe reservations, so coordination will
> need to be done by the clients.
>
> So if you want to have a subsystem with two shared namespaces and two
> clients connected, just write:
>
> [Subsystem1]
>   NQN nqn.2016-06.io.spdk:cnode1
>   Core 0
>   Mode Virtual
>   Listen RDMA 192.168.25.3:4420
>   SN SPDK0000000000001
>   Namespace Malloc0
>   Namespace Malloc1
>
> Start up the target with that config and then connect two clients to
> the same subsystem. They'll each see their own controller but share
> namespaces.
>
> The best way to think about NVMe controllers in NVMe-oF is that they're
> just sessions in the networking sense of the word. We even call them
> spdk_nvmf_session in our code, as opposed to spdk_nvmf_controller. This
> isn't an implementation choice that SPDK is making either - that's
> really the intended meaning of a controller in the NVMe-oF
> specification which sometimes refers to them as "controller sessions".
>
> >
> >
> > Regards
> > Ankur
> > _______________________________________________
> > SPDK mailing list
> > SPDK(a)lists.01.org
> > https://lists.01.org/mailman/listinfo/spdk
>
> _______________________________________________
> SPDK mailing list
> SPDK(a)lists.01.org
> https://lists.01.org/mailman/listinfo/spdk
>
>

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[SPDK] Namespace sharing between multiple controller

[Ankur Srivastava]

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Hi All,

I am using null block devices on my Target side and here is my conf file
snap (app/nvmf_tgt/nvmf_tgt -c etc/spdk/nvmf.conf.in)

[Subsystem1]
  NQN nqn.2016-06.io.spdk:cnode1
  Core 0
  Mode Virtual
  Listen RDMA 192.168.25.3:4420
  SN SPDK00000000000001
  Namespace Malloc0

[Subsystem2]
  NQN nqn.2016-06.io.spdk:cnode2
  Core 1
  Mode Virtual
  Listen RDMA 192.168.25.31:4420
  SN SPDK00000000000001
  Namespace Malloc1


How can I create multiple controllers and how can I share namespace
like(Malloc0, Malloc1) between different controllers ??


Regards
Ankur

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