Re: Command Queue Depth (was asymmetric/Symmetric)

["Matt Wakeley" <matt_wakeley@agilent.com>]

Joshua Tseng wrote:

> James,
>
> I agree with others that there may be an issue with the
> command windowing mechanism in the existing iSCSI spec.  It is like
> "TCP in reverse", in that the target determines the size of the window, and
> not the initiator as in TCP.  Rather, I believe that everything that this
> windowing mechanism is attempting to achieve can be more easily obtained
> by having the target communicate its buffer size to the initiator at
> iSCSI login.  It should be the role of the initiator to determine how
> many commands to put in flight simultaneously, given this input on available
> buffer size from the target.

As more initiators connect to a target, it may need to scale back the amount of
this buffering it has allocated to each previously logged in initiator (to
prevent rejecting new logins).

>
>
> As far as multiple initiators, could this not be resolved by the target
> refusing additional logins beyond the number of initiators it can safely
> support?  Not being a storage expert, this is my best guess/suggestion
> at how to do it.

I believe John already answered this...

-Matt