Re: Requirements specification

["Mark A. Carlson" <mark.carlson@sun.com>]

julian_satran@il.ibm.com wrote:
> 
> David,
> 
> The one additional requirement is availability/fault-tolerance.

Could you elaborate on this and tell us how multiple connections
between the same two NICs enhance availability?

Also, can you state what the availability requirements are?

> 
> Your arguments about performance are valid. However I doubt that there will
> be enough incentives - beyond price - to develop things for high end
> controllers and
> servers.
> 
> Enabling multiple connections brings those applications the performance
> required
> without any serious implications to the rest of the "family" (as I outlined
> in Pittsburgh
> controllers and servers that don't need multiple connections/session don't
> have to implement them).

The serious implications that I think everyone is concerned about is the
complexity that we are introducing into the protocol and the question of
whether this really provides the performance that is asserted.

> 
> Storage traffic requirements will always exceed those of many other
> applications.
> 
> As for the "one-connection-per-LU" we covered this solution in long
> discussions
> and even several full fledged implementation - as it is compelingly simple.
> However the resource consumption is unjustifiably high and the security
> problems are
> even worse (the LUs "viewed" by an initiator depend on who he says he is)
> than
> in the current draft.

Chances are that each LUN could be owned by separate initiators and require
authentication to separate principals anyway. I think that this is the
requirement we need to keep in mind.

-- mark