Re: [Scst-devel] [REQUEST TO TEST]: ALUA changes toward better SCSI compliance

[Bart V. A. <bar...@sa...>]

On 02/26/2016 03:45 PM, Sebastian Herbszt wrote:
> I just enabled explicit ALUA support in SCST and noticed STPG gets send
> down the standby path. I think it comes from the ALUA handler and not multipathd.
>
> multipathd: 26162356632353435: sdc - tur checker reports path is in standby state
> multipathd: 8:32: reinstated

Hello Sebastian,

This multipathd behavior has been introduced in 2009 (see also below). 
I'm afraid that anyone who is using an enterprise OS release around or 
before that date will see the previous multipathd behavior, namely that 
standby paths for which SCST fails TUR are considered failed by the 
initiator and hence that the initiator won't send an STPG over these paths.

Bart.

 From the multipath-tools changelog:

commit 5da642ff71254ecda685e82c681e78cab4c75b87
Author: Hannes Reinecke <ha...@su...>
Date:   Thu Feb 19 16:19:45 2009 +0100

     Return 'ghost' state when port is in standby

     Currently, issuing a TUR command on a path in standby
     mode, it returns a Unit Attention status. This is
     reported as a Failed path by the SLES11 tur checker.
     Instead, this has to be reported as Ghost path based
     on the additional sense code and sense code qualifier values.

     References: 475816

     Signed-off-by: Hannes Reinecke <ha...@su...>