Logical unit groups and optional target reset

Andrew Hisgen Andrew.Hisgen at Eng.Sun.Com
Tue Jan 2 11:47:43 PST 2001


* From the T10 Reflector (t10 at t10.org), posted by:
* Andrew Hisgen <Andrew.Hisgen at eng.sun.com>
*

> X-Authentication-Warning: t10.t10.org: lohmeyer set sender to 
owner-t10 at t10.org using -f
> From: Charles Monia <cmonia at NishanSystems.com>
> To: "Elliott, Robert" <Robert.Elliott at COMPAQ.com>, "'t10 at t10.org'" 
<t10 at t10.org>
> Subject: RE: Logical unit groups and optional target reset
> Date: Fri, 29 Dec 2000 17:27:55 -0800
> MIME-Version: 1.0
> X-Message-Number: 1499
> 
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Charles Monia <cmonia at NishanSystems.com>
> *
> Hi Rob:
> 
> See my remarks below.
> 
> > -----Original Message-----
> > From: Elliott, Robert [mailto:Robert.Elliott at COMPAQ.com]
> > Sent: Friday, December 29, 2000 2:11 PM
> > To: 't10 at t10.org'
> > Subject: RE: Logical unit groups and optional target reset
> > 
> > 
> 
> <material deleted>
> 
> > > The other issue is whether mechanisms, such as terget reset, 
> > > are appropriate for a given transport.  In my view, the only 
> > > immutable requirement is to preserve the transport-independant 
> > > part of the semantics.  The definition of transport-specific
> > > side effects is best handled in the appropriate transport
> > > specification.
> > 
> > The transport-independent parts are a major part of the 
> > problem.  Tasks are aborted, mode pages are reset, etc. 
> > unexpectedly.  Based on the rule from 99-245r9, devices 
> > offering Access Controls can be set up to behave better.
> > 
> 
> For a shared device, doesn't an LU reset have similar adverse side effects
> on other initiators?  This still leaves me wondering whether or not it would
> be better to restrict the operation altogether.

We need it to have those side-effects, when the device is wedged.
Yes, target reset is a powerful hammer, but we need it to unwedge
the device.  The fact that multiple initiators are affected is
kind of beside the point when the device is wedged anyway.
Thanks,
--Andrew Hisgen
Solaris Products Group,
Sun Microsystems Inc

> 
> Charles
> *
> * For T10 Reflector information, send a message with
> * 'info t10' (no quotes) in the message body to majordomo at t10.org

*
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at t10.org




More information about the T10 mailing list