iscsi : iscsi parameter default values

[Santosh Rao <santoshr@cup.hp.com>]

All,

With the issue of mode page vs. login keys having [almost] drawn to a close, I would like to
raise the below issues again, on the subject of default values for login keys and other iscsi
parameters :


   * In keeping with traditional use of scsi mode pages, iscsi should not specify any default
     settings for any mode pages that continue to exist for iscsi. "Default values" for mode
     pages are target specific and should not be bound to the protocol draft.

   * MORE IMPORTANTLY, I read the default for EMDP as being set to 1  :-<  This implies that
     targets must be always prepared to deal with out of order data and initiators must be
     prepared to deal with out of order data, unless the initiator performs a mode select to
     disable it. [which defeats all the previous advantages gained thru mandating use of login
     keys for other negotiations.]. A default, if it were to exist, should be 0. (in-order, by
     default).

   * Conservative specification of defaults for login keys along the following lines :
                            MaxConnections = 1
                            FMarker = "no"
                            InitialR2T = "yes"
                            BidiInitialR2T = "yes"
                            ImmediateData = "no"
                            DataPDULength = 16
                            MaxOutstandingR2T = 1
                            DataPDUInOrder = "yes"
                            ErrorRecoveryLevel = 0
                            SessionType = "normal"

   * Should the iscsi protocol require a "Lun Control Mode Page"? IOW, is an EnableCRN bit
     required at the transport layer ? If the device server capability is to be negotiated , I
     suggest this bit be moved to a SCSI ULP Mode Page such as the "Control Mode Page", through a
     T10 change as a part of the SCSI changes being driven by iscsi.

Comments ?

Thanks,
Santosh


Santosh Rao wrote:

> There are the separate issues of :
>
>    * iscsi's specification of defaults for its mode pages which is not in line with mode page
>      usage. This impacts the target's ability to enforce values other than the protocol
>      specified default, if the initiator were to not use mode sense/select.
>
>    * default settings for login keys.
>
>    * Is there a need for the "LUN Control Mode Page" and whether "Enable CRN" should be in a
>      transport specific mode page ?
>
> which need to be driven to closure as well.
>
> Regards,
> Santosh
begin:vcard 
n:Rao;Santosh 
tel;work:408-447-3751
x-mozilla-html:FALSE
org:Hewlett Packard, Cupertino.;SISL
adr:;;19420, Homestead Road, M\S 43LN,	;Cupertino.;CA.;95014.;USA.
version:2.1
email;internet:santoshr@cup.hp.com
title:Software Design Engineer
x-mozilla-cpt:;21088
fn:Santosh Rao
end:vcard