[linux-lvm] Editing LVM 2 metadata

himanshu padmanabhi himanshu.padmanabhi at gmail.com
Mon Nov 17 13:29:40 UTC 2008

*Is this issue having connection with it.


One IET target is having 2 luns as "Parent LV" and "its snapshot".

When MS initiator connects to it,it gets rebooted.

I came to know through forum that it is due to same disk signatures of the
two disks on initiator side.

If I attach "Parent LV" and "its snapshot" to different targets,then windows
initiator is behaving well.

But in Open-iSCSI initiator under linux,both cases work well,

*both parent lv and its snapshot are taking same IDs probably.How can i
change the id of snapshot.It determines ID internally through timestamps and
some other things.Both takes UUID obviously different.Windows might see
these either as two copies of the same volume or two paths to the same
volume, but their data diverges which causes Windows to freak out.Windows
stores a volume identifier in the MBR/GPT when a disk is first recognized
and uses that identifier for identification of storage volumes.But I cannot
make changes on client(initiator) side as my product is server machine.

basically *what changes should be made on the target side so that initiator
will recognize both as different disks?*

On Sat, Nov 15, 2008 at 6:14 PM, David Robinson <zxvdr.au at gmail.com> wrote:

> 2008/11/15 Michael Jensen <beachhangar at yahoo.com>:
> > The why is because I am attempting to use storage managed snapshots.  The
> > storage can present the master volume and the snapshot as separate LUN's
> but
> > they present identical contents in the header area (first 256
> sectors...).
> > So the effort is to modify the snapshot (doable with this storage)
> without
> > altering the contents of the master volume.  Hopefully the snapshot with
> > suitable edits to the UUID's would then pass vgscan test.
> Its easiest if you follow the steps listed here:
> https://www.redhat.com/archives/linux-lvm/2007-November/msg00039.html
> --Dave
> _______________________________________________
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> linux-lvm at redhat.com
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Himanshu Padmanabhi
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