[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Google
  Web www.spinics.net

Re: Send Reject PDU when orignal to-be-rejected PDU is notavailable



Jason,
 
The CmdSN window allows the target to control the resources consumed
by commands.  I don't understand the need to save "all PDU header
comes from the Initiator until corresponding statSN is explicitly
ACKed".  What purpose is that accomplishing (e.g., why save all
the iSCSI Data-Out PDU headers for a SCSI WRITE)?
 
In any case, the original PDU header is required for a Reject in order
for the initiator to figure out what was rejected.  If the initiator
cannot figure that out, it is going to have a very difficult time
recovering from the Reject.
 
Thanks,
--David

----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
black_david@xxxxxxx        Mobile: +1 (978) 394-7754
----------------------------------------------------


From: ips-bounces@xxxxxxxx [mailto:ips-bounces@xxxxxxxx] On Behalf Of HUJason
Sent: Tuesday, April 15, 2008 11:46 PM
To: Black, David; ips@xxxxxxxx
Subject: Re: Send Reject PDU when orignal to-be-rejected PDU is notavailable
 

Hi David,

Thank you for the suggestion. A little more to consider is that it seems that whatever mechanisms we use, as a target, we must reserve all PDU header comes from Initiator until the coressponding statSN is explicitly acked. For a resource-limted iscsi target engine(all SCSI data is on host, so it is not in this question), It can be considered as a big memory consumer and becomes a bottlenack.


Best Regards,
Jason

From: Black_David@xxxxxxx
Subject: RE: Send Reject PDU when orignal to-be-rejected PDU is notavailable
Date: Tue, 15 Apr 2008 23:04:15 -0400
To: hzj_wuying@xxxxxxxxxxx; ips@xxxxxxxx

The original PDU header has to be sent back so that the initiator
knows what was rejected.  iSCSI has a number of mechanisms that
can be used by the target to control resource consumption and
those should be used to ensure that adequate resources are
available to deal with the PDU that is to be rejected.
 
Thanks,
--David
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
black_david@xxxxxxx        Mobile: +1 (978) 394-7754
----------------------------------------------------


From: ips-bounces@xxxxxxxx [mailto:ips-bounces@xxxxxxxx] On Behalf Of HUJason
Sent: Tuesday, April 15, 2008 9:59 PM
To: ips@xxxxxxxx
Subject: Send Reject PDU when orignal to-be-rejected PDU is notavailable

Dears,
I am curently implement iscsi target on a resource-limted device. In my implementation, orignal to-be-rejected PDU is not available when it realised that a Reject should be sent to initiator.
 
But as RFC3720 said, Target must send back the orignal PDU as the Reject's payload.
 
So my question is: Why we need to send back the orignal PDU ? Can we simply eliminate it?
 
Thanks!

Best Regards,

Jason 



“七件武器,七种完美” 立刻体验!


Windows Live Writer,支持离线撰写博客内容,随时随地想写就写。 立即使用!
_______________________________________________
Ips mailing list
Ips@xxxxxxxx
https://www.ietf.org/mailman/listinfo/ips

[IETF]     [Linux iSCSI]     [Linux SCSI]     [Linux Resources]     [Yosemite News]     [IETF Announcements]     [IETF Discussion]     [SCSI]

Add to Google Powered by Linux