Subject: Re: [vserver] vserver and iscsi kernel panic
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Wed, 25 Feb 2009 01:08:16 +0100

On Tue, Feb 24, 2009 at 11:30:28AM -0500, John A. Sullivan III wrote:
> On Tue, 2009-02-24 at 11:36 +0100, Herbert Poetzl wrote:
> > On Tue, Feb 24, 2009 at 02:56:36AM -0500, John A. Sullivan III wrote:
> > > Hello, all. I am running VServer kernel 2.6.22.19-vs2.3.0.34.1 on
> > > CentOS 5.2 with iscsi-initiator-utils 2.0.868-0.7.el5 in amd64 with
> > > two quad core 2378 CPUs. Whenever we try to login to an iSCSI target,
> > > we receive a kernel panic. Is this a known issue? How does one
> > > stabilize it? 
> > 
> > once again my crystal ball failed me as it couldn't
> > create a crispy clear image of your kernel panic :)
> <snip>
> OK - now I'm more panicked than the kernel! (and ready to reveal even
> more ignorance) This is apparently a known bug in open-iscsi:

> "In 2.6.22 and below there is bug where open-iscsi does not handle some 
> of the packets we got from open solaris correctly. It is not open 
> solaris's fault and was a driver bug."

well, stable doesn't mean bug-free, it just means
that it was well tested and can be considered stable
for 'normal' use (I think debian defines stable a
little different though ... :)

> Since this is planned to be both a complex and heavily taxed production
> environment, I've been trying to stay well "within the lines" by using
> the CentOS dhozac repository RPMs.  However, these are kernel 2.6.22.

> Anything newer is labeled experimental on the VServer download page.
> Any recommendations for a very stable experimental kernel to use? 


2.6.27.x is said to be long-term maintained by mainline
and thus we will also provide long-term maintainance to
the related Linux-VServer patches, so probably that would
be a good choice ...

> Are there any problems using a much newer kernel than normally ships
> with CentOS 5.2? Would there happen to be any RPMs available as I do
> not want my ignorance of our systems requirements to show up in a
> misconfigured custom compiled kernel and would like to eventually be
> able to revert to the repositories.

no idea, probably Daniel known more in this regard ...

> Worse comes to worst, I will take the plunge and build a custom kernel
> as I used to do for our IPSec gateways years ago.

IMHO building a 'custom' kernel is the only sane way
to setup a performant and reliable system, at least
I would always prefer a lean and clean kernel over a
distribution one-kernel-fits-all monster, but YMMV

best,
Herbert

> Thanks - John
> -- 
> John A. Sullivan III
> Open Source Development Corporation
> +1 207-985-7880
> jsullivan@opensourcedevel.com
> 
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