[DRBD-user] Linstor: consistency of device node numbers

[Roland Kammerer]

On Sat, Feb 13, 2021 at 11:32:21AM +0000, Brian Candler wrote:
> On 12/02/2021 18:34, Brian Candler wrote:
> > In my testing, Linstor seems to create the same device node name on each
> > node (e.g. `/dev/drbd1000`).
> > 
> > My question is: is this guaranteed?  e.g. is the drbd node number a
> > unique, global property of the volume itself?
> 
> I think I've answered my own question here:
> 
> root at node1:~# linstor volume-definition list -p
> +---------------------------------------------------------------+
> | ResourceName | VolumeNr | VolumeMinor | Size  | Gross | State |
> |===============================================================|
> | my_ssd_res   | 0        | 1000        | 1 GiB |       | ok |
> | res00        | 0        | 1001        | 1 GiB |       | ok |
> | res00        | 1        | 1002        | 2 GiB |       | ok |
> +---------------------------------------------------------------+
> 
> The VolumeMinor appears to be a property of the (Resource+Volume),

yes.

> so I think it should be stable and consistent across all nodes where
> that resource appears. 

yes. LINSTOR has a pool and generates a free one and remembers it. So it
is consistent for that res/vol combination on all nodes. If you delete a
resource/volume and generate a new one, it might reuse this now free
minor again. But still, consistent on all nodes in the cluster.

Regards, rck