iSCSI : Abort Task "connection allegiance"

["Santosh Rao" <santo_rao@hotmail.com>]

>To: ips@ece.cmu.edu Subject: iSCSI-related conclusions from Orlando interim 
>Meeting From: Black_David@emc.com Date: Fri, 19 Jan 2001 19:29:36 -0500

>(2) Error Recovery
>- Abort WARNING will be added to the draft.
>- Immediate Delivery of Aborts and similar task management commands
>   may have unexpected results when multiple TCP connections are in use
>   because Abort, Clear Task Set, etc. may bypass command(s) to be
>   aborted/cleared on other TCP connections.
>- Ordered Delivery should be used instead when this is a concern.

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Julian & All,

For the above issue, the Abort Task I/O Error Recovery is udertaken
when an I/O times out (O.S. specific SCSI ULP timer has expired). Under
such circumstances, it is preferrable to have an expedited error
recovery which is not hindered by stalls in its processing due to the
target waiting for missing CmdSNs.
[which are applicable when the Abort Task is sent with a non-0 CmdSN].

In the interests of keeping I/O timeout recovery quick, the
"connection allegiance" policy, currently applicable to all phases of a
command, should be extended to the Abort Task for that command as well
and the Abort Task be sent with a CmdSN of 0.

Regards,
Santosh

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