[stgt] Limiting the number of ISCSI-Sessions per target

[Arne Redlich]

Am Montag, den 20.10.2008, 11:49 +0900 schrieb FUJITA Tomonori:
> On Fri, 17 Oct 2008 18:05:14 +0200
> "Dr. Volker Jaenisch" <volker.jaenisch at inqbus.de> wrote:
> 
> > Hello stgt developers!
> > 
> > I have a HA XEN-setup based on ISCSI devices [tgtd (target) and
> > open-iscsi (initiator)]
> > as physical devices for the XEN DomUs.
> > 
> > In case of a split-Brain in the HA-System more than one machine may
> > fetch a iSCSI-Session and may try to bring up a XEN-VM on it. This will seriously damage the
> > filesystem.
> > 
> > Therefore I like to limit the number of iSCSI sessions to one 
> > session per target, simultaneously
> > 
> > Is there a way to limit the number of ISCSI-Sessions per Target-ID?
> > I found the MaxConnection-Parameter but it limits only the number of
> > connections within a single iSCSI-Session.
> 
> Yeah, MaxConnection is iSCSI legitimate parameter.
> 
> 
> > Is there something alike - say a MaxSession-Parameter?
> 
> There is no standard way to do such. IET used to support MaxSessions
> parameter to limit the maximum number of sessions per target. We could
> add the same feature to tgt, but IET disables the feature now. Anyone
> can recall why? Well, probably I disabled it but I can't recall
> anything.

It was disabled it because we could not detect whether the initiator
holding this "lock" was alive. IMO such a parameter really requires
proper NOP-In support.

HTH,
Arne

--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html