[PATCH nvme-cli rfc 0/6] Support discovery log change events

[sagi@grimberg.me (Sagi Grimberg)]

>>> We shouldn't unite them. They are very different things.? One is an 
>>> event that says I found a discovery controller go probe it, while the 
>>> other is a discovery controller saying I have a discovery log entry 
>>> go connect to it.?? My position is we should have both.
>>
>> Well I agree with you, but these the question is would userspace do
>> something different for each? As of now it doesn't.
> 
> I would think it would do something different. What we don't do well 
> currently is specify per-connection parameters - when automated. That's 
> where I see the difference.
> 
> I would think parameters for the discovery controller should be separate 
> from parameters for? storage controllers. So the scripts could use two 
> different config files to look up defaults or per-connect values.
> 
> For example, the discovery controller probe request can look at a 
> discovery_connect.cfg, obtain defaults or a tr-addr-based match for say 
> ctrl-loss-timeout, whether to be long-lived, and if long-lived what the 
> keep-alive-tmo should be.
> 
> While the connect request can look at storage_connect.cfg, use the 
> tr-addr-values and nqn to determine if it should not be connected to 
> (default is yes), and if connecting, defaults or any tuning based on nqn 
> or tr-addr-values to use for the connect.

I do have a plan to add something like params.cfg that nvme connect
would assemble for the connect string, but isn't that orthogonal
to the the action taken for both events?