Re: [linux-lvm] Simulating LVM Mirror Failure and recovery

[Don Bishop <donbishop@mediacell.com>]

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Hey Eric

Nice to see your still around. How's it all going?

best,
Don B



On Thu, 2009-04-16 at 07:58 -0600, Eric Brunson wrote:

> On 04/16/2009 07:36 AM, Eric Brunson wrote:
> > On 04/16/2009 06:54 AM, Alasdair G Kergon wrote:
> >> On Thu, Apr 16, 2009 at 07:07:57AM -0500, vu pham wrote:
> >>> yogeen honnavar wrote:
> >>>> Dear users,
> >>>> dd if=/dev/zero of=/dev/vg1/lv1 count=10
> >>>> as per the redhat guide this should result in mirror leg failure 
> >>>> and any
> >>
> >> Can you provide the reference - where does it say this?
> >>
> >> Alasdair
> >
> > I believe this is the reference.
> >
> > http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Cluster_Logical_Volume_Manager/mirrorrecover.html 
> >
> >
> > Their example may be in error.
> >
> >
> 
> Upon review, I think it's correct, but worded awkwardly:
> 
>     In this example, the primary leg of the mirror |/dev/sda1| fails.
>     Any write activity to the mirrored volume causes LVM to detect the
>     failed mirror. When this occurs, LVM converts the mirror into a
>     single linear volume. In this case, to trigger the conversion, we
>     execute a |dd| command
> 
>     [root@link-08 ~]#*|dd if=/dev/zero of=/dev/vg/groupfs count=10|*
>     10+0 records in
>     10+0 records out
> 
> 
> I believe the dd is not to cause the failure, it's simply to generate 
> write activity to the volume group after the mirror leg has been caused 
> to fail through other means not documented.
> 
> Anyone else think that's the case?
> 
> e.
> 
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> 

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