[stgt] make initiators "rescan" the device?

[FUJITA Tomonori]

On Thu, 30 Oct 2008 18:09:22 +1100
"ronnie sahlberg" <ronniesahlberg at gmail.com> wrote:

> On Thu, Oct 30, 2008 at 11:04 AM, FUJITA Tomonori
> <fujita.tomonori at lab.ntt.co.jp> wrote:
> > On Wed, 29 Oct 2008 12:26:58 +0100
> > Tomasz Chmielewski <mangoo at wpkg.org> wrote:
> 
> >> Is it possible to send a reset/rescan to all initiators connected to a
> >> given target, which would trigger the initiator to rescan the device
> >> (and its size)?
> >
> > A scsi device can notify initiators of such event via UA (unit
> > attention), google "CAPACITY DATA HAS CHANGED". tgt has the mechanism
> > to handle UA so it's easy to support it. However, on the initiator
> > side, Linux doesn't detect such event automatically.
> > --
> 
> I guess this is dependent on the transport, but at least for iSCSI the
> way to do this by sending an AsynchronousRequest to the initiator.
> To send to connected initiators when a lun changes in size,
> also to all connected (and affected) initiators if the lun masking
> changes for the target.

I guess that you are talking about SCSI Asynchronous Event Reporting,
right?

SAM-3 has made it obsolete. The proper way to notify initiators of an
event is UA now. And I'm not sure there is a standard way to notify
initiators of the device resize via AER.


> Are you saying that Linux initiators do not understand AsyncRequest PDUs ?

At least, open-iscsi doesn't support it, I think.
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