[dm-devel] Configuring multipath for root device

[Pradipmaya Maharana]

Hey Ben,

Thanks for your inputs. I will give it another try and let you know if
it worked.

Regards,
Pradipmaya.

On 12/21/07, Benjamin Marzinski <bmarzins at redhat.com> wrote:
> On Thu, Dec 20, 2007 at 08:46:41AM -0800, Pradipmaya Maharana wrote:
> > Hi,
> >
> > Pardon my knowledge on Linux, but in your article did you mean that
> > the /boot should be on a local disk and /root, swap can be on
> > multipath device.
> >
> > I am trying to install /boot, /root and swap all on one multipath
> > device and try to boot from it. It does not boot, no error just blank
> > screen. My equirement is to install everything on multipath device; so
> > is it possible at all? I mean can I have the boot device (/boot) too
> > on a multipath device.
> >
> > Following is what I tried on RHEL
> >  - selected "linux mpath"
> >  - I could see one local disk and 3 multipath devices
> >  - I chose custom partition type
> >  - instead of going for LVM, I selected one single multipath device
> > and installed everything on it (/boot, / and swap).
> >  - Tried rebooting, it won't boot :(
> >
> > What am I missing here?
>
> I haven't ever tried putting swap on a multipath device, but I believe
> it should work.  Your steps seem correct. Are you getting any messages
> at all on the console when you boot up?
>
> One thing you need to be aware of is that while multipathed root is
> pretty simple, for multipathed boot to work, your machine needs to be
> able to boot from the device that your are multipathing with no help
> from any linux device drivers (since they obviously can't be loaded
> until you run the boot loader).  I believe some machines need something
> to be set in BIOS in order to try and boot off SAN storage.
>
> To narrow down the problem, I would try setting up the same
> configuration, but without multipathing the device. If this doesn't
> work, then you are probably having problems booting from your storage.
> If it does work, then when you set it up with multipathing, you should
> at least be making it past GRUB, and looking at the console output
> should shed some light on what's going wrong.
>
> Note, if you have a device that needs a prio_callout, multipath will
> still fail in the all paths down case, because it can't access the
> callout program.  The upstream code currently fixes that by using
> callout library functions, and the next device-mapper-multipath package
> from RHEL will fix it by caching the callouts in a private namespace.
>
> -Ben
>
> > Thanks and Regards,
> > Pradipmaya.
> >
> >
> > On 12/19/07, Pradipmaya Maharana <pradipmaya at gmail.com> wrote:
> > > Hi Chandra,
> > >
> > > Thanks. I will givei it a try.
> > >
> > > Regards,
> > > Pradipmaya.
> > >
> > > On 12/19/07, Chandra Seetharaman <sekharan at us.ibm.com> wrote:
> > > > I am working on a multipath usage document. Attached is the installation
> > > > section of that document.
> > > >
> > > > Note that it is written for RHEL5 U1 and SLES10 SP1.
> > > >
> > > > Good Luck,
> > > >
> > > > chandra
> > > >
> > > > On Wed, 2007-12-19 at 13:02 -0800, Pradipmaya Maharana wrote:
> > > > > Hi All,
> > > > >
> > > > > Is there a process/document that talks about how to configure
> > > > > root/boot device for multipath?
> > > > >
> > > > > Thanks and Regards,
> > > > > Pradipmaya.
> > > > >
> > > > > --
> > > > > dm-devel mailing list
> > > > > dm-devel at redhat.com
> > > > > https://www.redhat.com/mailman/listinfo/dm-devel
> > > > --
> > > >
> > > > ----------------------------------------------------------------------
> > > >    Chandra Seetharaman               | Be careful what you choose....
> > > >              - sekharan at us.ibm.com   |      .......you may get it.
> > > > ----------------------------------------------------------------------
> > > >
> > > >
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> > > >
> > > >
> > >
> >
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