[rear-users] REAR restore on multipath

reynald CHEKHINA r.chekhina at gmail.com
Mon Feb 18 12:54:15 CET 2013


HI,

I'm using friendly name define in /etc/multipath.conf (wwid, alias) .
I' have change root to /mnt/local/ recreate my initrd with mkinitrd.
Multipath is activate.

My workaround is boot on rhel dvd start on linux rescue mpath and recreate
mkinitrd.
My server restart well.

So It's strange ! I want to bypass this workaround.

2013/2/18 Gratien D'haese <gratien.dhaese at it3.be>

> Hi,
>
> It would be nice if you could create an issue tracker for this interesting
> problem.
>
> I see 3 potential problems so far:
> 1/ by using friendly names is not a guarantee that the the same SAN-device
> names are used after the reboot. It is better to use the by-id paths. I
> wouldn't rely on friendly names or aliases in recovery mode
> 2/ did you recreate the initrd with mkinitrd?
> 3/ did you add the multipathd and boot.multipath services at boot time?
>
> regards, Gratien
>
> On Sun, 17 Feb 2013 21:07:36 +0100, reynald CHEKHINA <r.chekhina at gmail.com>
> wrote:
>
> Hello,
>
> I have add multipath to boot iso, load module dm_multipath create
> multipath with multipath -v3 and see mpath0. A launch rear recover and
> change disklayout.conf file with mpath0, mpath0p1 .... creation and
> restoration works well. After i change root to /mnt/local i modify
> /etc/multipath.conf, /etc/fstab, /var/lib/multipath/bindings,
> /etc/lvm/lvm.conf and /etc/sysconfig/mkinitrd/multipath. I recreate grub to
> map on / dev/mapper/mpath0 recreate initrd .
> I reboot the server but i have a kernel panic message :
>
> mount: could not find filesystem '/dev/root'
> setuproot: moving /dev failed: No such file or directory
> setuproot: error mounting /proc: No such file or directory
> setuproot: error mounting /sys: No such file or directory
> switchroot: mount failed: No such file or directory
> Kernel panic - not syncing: Attempted to kill init!
>
> Can you help me please ?
>
> On Thu, 14 Feb 2013 16:48:16 +0100 (CET), Dag Wieers wrote:
> > On Thu, 14 Feb 2013, reynald CHEKHINA wrote:
> >
> >> I migrate physical machine RHEL5.4 with local disk to other physical
> >> machine with boot on san. When I try to restore I see only /dev/sda-d of
> >> 4 path lun and don't see mpath.
> >> It's possible to restore on mulitpath /dev/mpath ?
> >
> > Since the original system does not use multipathing itself, the rescue
> > image does not have it included. And it's even possible that the original
> > system doesn't have multipath tools installed at all.
> >
> > What you currently can do to work around this is:
> >
> >   - Include the multipath tools manually in the configuration
> >   - Create an additional script that starts multipathd during rescue boot
> >
> > But we could discuss how we want to do this in the future. In this case we
> > could always include multipathd if it is on the original system, and run
> > it on rescue boot. It can be useful, and is harmless (?) if there's no
> > multipathing.
> >
> > Same for backup methods, having other tools included (e.g. rsync, ...)
> > when installed, gives more options during restore.
> >
> I'm sure he will end at issue https://github.com/rear/rear/issues/183
> Our code is not 100% ready yet for migrating to SAN-only disks. Need some time to continue work on this. Unfortunately, time is not my best friend these days ;-(
>
>
> Gratien
>
>
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>
>
>
> --
>
> Gratien D'haese
> IT3 Consultants bvba
> Vennestraat 15, B-2560 Nijlen
>
>
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>
>


-- 
Cordialement

CHEKHINA Reynald
tel : 06.64.94.96.42
mail : r.chekhina at gmail.com
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