RE: iscsi : default iscsi mode page settings.

["Sanjeev Bhagat (TRIPACE/Zoetermeer)" <sbhagat@tripace.com>]

John,

the firstburstsize will not be included in the SCSI device driver. It has to
be done either by iscsi driver or any application passsing command to iscsi
driver.

Firstburstsize parameter depends on the buffer capacity of the Target and
application client. In most cases this will be a limitation at target's end
which has limited buffersize in which it can take the data from service
delivery subsystem. The application client on other hand can keep queuing
the requests and ask the data from the OS corresponding to the command.

The role of SCSI driver is to pass the commands as it is to the lower layer
in the stack. It does not probe any CDB, although it is fully capable of
doing it.


Regards,
Sanjeev



-----Original Message-----
From: John Hufferd [mailto:hufferd@us.ibm.com]
Sent: Wednesday, September 26, 2001 4:37 PM
To: CONGDON,PAUL (HP-Roseville,ex1)
Cc: 'cbm@rose.hp.com'; ips
Subject: RE: iscsi : default iscsi mode page settings.



Does anyone know of where a Legacy function would exist, in the Host which
would do anything with FirstBurstSize?  I am assuming it would have to be
in the SCSI Device Driver, and since we have iSCSI instead, that may not be
an issue.
I could be wrong but I do not think that it occures in the SCSI Class
Drivers.
And I do not think it ocures in the File Systems, so where does this Legacy
function we are worried about occure?
If it is in the SCSI Device Driver it is NOT an issue.

.
.
.
John L. Hufferd
Senior Technical Staff Member (STSM)
IBM/SSG San Jose Ca
Main Office (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
Home Office (408) 997-6136
Internet address: hufferd@us.ibm.com


"CONGDON,PAUL (HP-Roseville,ex1)" <paul_congdon@hp.com>@ece.cmu.edu on
09/25/2001 10:14:12 PM

Sent by:  owner-ips@ece.cmu.edu


To:   "'cbm@rose.hp.com'" <cbm@rose.hp.com>, ips <ips@ece.cmu.edu>
cc:
Subject:  RE: iscsi : default iscsi mode page settings.




>Julian and Santosh,
>
>Whether FirstBurstSize should be a text key or not,
>IMHO, is (mostly) dependent on the current implementations.
>Santosh rightly pointed out several drawbacks of
>mandating a new set of mode select/sense operations
>that are totally iSCSI-specific since the legacy SCSI
>stack (class drivers, services/midlayer) will have no
>clue about them.  OTOH, if most of today's SCSI stacks
>_do_ perform this mode parameter manipulation in disconnect-
>reconnect mode page, that would be a strong argument to
>leave FirstBurstSize as a mode page parameter.

Anything iSCSI specific should attempt to follow other iSCSI
methods of configuration (e.g. text keys).  We should really
be driving towards a single method of parameter negotiation
and configuration - especially when the legacy methods
have no clue about the new parameters and would require upgrades.

Paul