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On 26/04, wodel youchi wrote:
> Hi,
>
> The examples I could find on the internet using LVM as backend for Cinder,
> they expose a local disk using lvm via Cinder.
>
> I did this configuration and I am wondering if it's correct, especially
> from a "simultaneous access" point of view.
>
> I have an iSCSI target backed by targetcli that exposes a LUN to my compute
> nodes. I did configure the iscsi connexion manually on each one of them and
> they all see the LUN, then on one of them I created the cinder-volumes VG
> (the other nodes can see the modifications), then I configured Cinder with
> lvm backend using this VG and it worked. I created some volumes on it
> without issues using my account. But what about when there are multiple
> tenants that try to create multiple volumes on it, is this configuration
> safe?
>
> Regards.

Hi,

I don't understand which of these 2 scenarios you have:

- You are sharing an LVM volume manually without using Cinder with each
  compute node and then you want to use the same LVM VG with Cinder for
  dynamically allocated volumes.

- You manually connected a volume to each compute to confirm that
  everything was working as expected and then you disconnected them and
  are using Cinder to dynamically allocate volumes for computes.

Even though I don't understand which one is your scenario, it doesn't
matter as both should be safe as long as the target iqn you defined for
your manual volumes don't use the same format as cinder volumes (to
avoid possible collision with a volume created from Cinder) because
Cinder LVM+LIO uses a per-volume target, so there won't be conflict with
the ones you create manually nor will Cinder touch what you already have
there.

Cheers,
Gorka.