Itamar, I concur with you.
I am aware of the dangers here (I edited metadata once already to test recovering a storage domain in a test setup).
It took me a few tries and looking through the code that generate and manipulates that data to get it right.

However perhaps as a feature request it would be prudent to allow for the ability to choose or change which domain is the master without taking down all the other domains. If you have a-lot of domains this really becomes problematic to play musical chairs with the domains to get the one you want to be master elected. This also requires you to take down VM's which makes it even more problematic. Can we get a "make this domain the master" feature added to the UI/Cli?

 -DHC

On Thu, Nov 1, 2012 at 2:07 AM, Itamar Heim <iheim@redhat.com> wrote:
On 11/01/2012 03:01 AM, Dead Horse wrote:
This is good info. Given that the metadata can be edited is there a way
to redesignate which storage domain should be the master? I have run
into a couple of times in which for various reasons the master domain
could not be reached and another storage domain was elected as master.
Is there a way to force an election or edit the metadata to redesignate
the original master domain back "as master" again?

i heartly suggest to not try and mess with that on your own.
you can move other storage domains to maint, to force engine to reconstruct the master on another domain.
(again, do *not* do it on your own via metadata)


- DHC

On Wed, Oct 31, 2012 at 12:43 PM, Itamar Heim <iheim@redhat.com
<mailto:iheim@redhat.com>> wrote:

    On 10/31/2012 07:36 PM, Simon Grinberg wrote:



        ----- Original Message -----

            From: "Itamar Heim" <iheim@redhat.com <mailto:iheim@redhat.com>>
            To: "Michael Ayers" <ayersmj@redhat.com
            <mailto:ayersmj@redhat.com>>
            Cc: users@ovirt.org <mailto:users@ovirt.org>

            Sent: Tuesday, October 30, 2012 10:57:52 PM
            Subject: Re: [Users] Documentation: Storage Domain
            conversion from Data Domain to Export Domain

            On 10/30/2012 09:29 PM, Michael Ayers wrote:

                Hey All,

                I ran into this issue myself where I needed to convert a
                data
                domain to
                an export domain in order to recover virtual guests from a
                corrupted
                ovirt/rhevm instance into a new ovirt/rhevm instance.
                  This wasn’t
                documented anywhere that I saw but with the help of
                Itamar Heim and
                an
                well timed email to the list from Igor Lvovsky last
                night I was
                able to
                do this and wanted to send to the list a documented
                procedure for
                how to
                modify the metadata of the data domain prior to import
                as an export
                domain.  This procedure works for both RHEV-M and Ovirt.
                  Let me
                know if
                you have any questions.


            glad it worked.


        Will this work if the recovered storage domain was not the master?


    no. only for nfs storage domain, only if it was master.




            care to wikify for others?

            thanks,
                 Itamar


                Original Data Domain Metadata File

                ------------------------------__--------------------


                CLASS=Data

                DESCRIPTION=vm-storage

                IOOPTIMEOUTSEC=10

                LEASERETRIES=3

                LEASETIMESEC=60

                LOCKPOLICY=

                LOCKRENEWALINTERVALSEC=5

                MASTER_VERSION=2

                POOL_DESCRIPTION=MyPool

                POOL_DOMAINS=dd8bc200-6e28-__4185-bfe0-f0affb94f283:Active,__ddefdf6c-ef68-419c-9f72-__76d27bf7d788:Active,66b3b243-__6cc6-465f-b130-6f2cd0b70514:__Active

                POOL_SPM_ID=2

                POOL_SPM_LVER=17

                POOL_UUID=a207f052-f4bf-44a3-__b637-c6d2020a7c41

                REMOTE_PATH=nfsserver:/ovirt/__vm-storage

                ROLE=Master

                SDUUID=66b3b243-6cc6-465f-__b130-6f2cd0b70514

                TYPE=NFS

                VERSION=0

                _SHA_CKSUM=__009fa538321ac56749669127f43cc7__54aa59d398


                Diff between Original DD Metadata File and ED Metadata File

                ------------------------------__--------------------


                --- metadata-data-storage       2012-10-30
                12:24:52.484006958 -0700

                +++ metadata-exp-storage        2012-10-30
                12:14:59.043807789 -0700

                @@ -1,5 +1,5 @@

                -CLASS=Data

                -DESCRIPTION=vm-storage

                +CLASS=Backup

                +DESCRIPTION=export-storage

                IOOPTIMEOUTSEC=10

                LEASERETRIES=3

                LEASETIMESEC=60

                @@ -7,13 +7,12 @@

                LOCKRENEWALINTERVALSEC=5

                MASTER_VERSION=2

                POOL_DESCRIPTION=MyPool

                -POOL_DOMAINS=dd8bc200-6e28-__4185-bfe0-f0affb94f283:Active,__ddefdf6c-ef68-419c-9f72-__76d27bf7d788:Active,66b3b243-__6cc6-465f-b130-6f2cd0b70514:__Active

                +POOL_DOMAINS=

                POOL_SPM_ID=2

                POOL_SPM_LVER=17

                -POOL_UUID=a207f052-f4bf-44a3-__b637-c6d2020a7c41

                -REMOTE_PATH=nfsserver:/ovirt/__vm-storage

                -ROLE=Master

                +POOL_UUID=

                +REMOTE_PATH=nfsserver:/ovirt/__export-storage

                +ROLE=Regular

                SDUUID=66b3b243-6cc6-465f-__b130-6f2cd0b70514

                TYPE=NFS

                VERSION=0

                -_SHA_CKSUM=__009fa538321ac56749669127f43cc7__54aa59d398

                Thanks,

                Michael

                ------------------------------__-------


                Michael J. Ayers

                Red Hat Inc.

                Solutions Architect

                e: ayersmj@redhat.com <mailto:ayersmj@redhat.com>
                <mailto:ayersmj@redhat.com <mailto:ayersmj@redhat.com>>

                w: www.redhat.com <http://www.redhat.com>
                <http://www.redhat.com/>



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