Live Migration is possible when the relevant storage server is not the one needing to be taken offline for maintenance. Granted a proper Gluster setup would alleviate that however when optimum performance of file backed virtual disks is a factor Gluster is not there yet.
- DHC


On Sun, Aug 18, 2013 at 5:47 AM, Ayal Baron <abaron@redhat.com> wrote:


----- Original Message -----
> Pausing the VM's can work in certain situations for simple maintenance.
> However suppose the purpose of the storage shutdown is to move data around
> for certain VM's or perhaps change that particular underlying storage

Then why not live migrate the relevant disks?

> filesystem or hardware. Thus some of the VM's will have to be down for sure
> however pausing them all because of the aforementioned would not be an
> option since it would take hours or days depending on the amount of data and
> the degree of change.
>
> - DHC
>
>
> On Fri, Aug 16, 2013 at 12:14 AM, Karli Sjöberg < Karli.Sjoberg@slu.se >
> wrote:
>
>
>
> tor 2013-08-15 klockan 10:46 -0500 skrev Dead Horse:
>
>
> Itamar this is true (I have noted occasional timing issues with it actually
> working).
> But what if as the administrator I have a specific storage domain in mind
> that I would like to have become the master (in the case of more then two)?
>
>
>
>
> @Karli
>
>
>
> The idea is not to not have to shut down all the VM's or the engine just to
> maintenance a storage domain(s) that may happen to be on disparate storage
> servers
> .
>
> Yes I understood that. My suggestion was a workaround until such operations
> are possible, that we use to minimize downtime as much as possible, to pause
> the VM's, shut down engine, maintenance, bring engine and VM's back. Since
> the VM's only was paused and engine shut down, the VM's just continue going
> happily unknowing exactly from where they were, and a reboot of a storage
> takes at most 5mins, which means 5mins total of downtime in the cloud
> environment for that quarter, which is acceptable for just about any SLA.
>
> /Karli
>
>
>
>
>
>
>
> - DHC
>
>
>
>
>
>
>
> On Thu, Aug 15, 2013 at 9:37 AM, Itamar Heim < iheim@redhat.com > wrote:
>
>
>
> On 08/15/2013 06:18 AM, Dead Horse wrote:
>
>
>
>
>
>
>
> Is there any method of designating which domain should be the master
> storage domain or forcibly changing the role to a different storage domain?
>
> EG: Given the following example
>
> Storage Domain A (Master) --> NFS --> Storage Server 1
> Storage Domain B --> NFS --> Storage Server 2
>
> One wants to do maintenance to Storage Server 1 but in doing so the
> Master storage domain is hosted from Storage Server 1. Thus the net
> result of taking down Storage Server 1 is that one must also take down
> Storage Server 2.
>
> Thus we know we must shut down VM's from Storage Domain A to maintenance
> Storage Server 1. Suppose however that VM's are running that we don't
> want to shut down and are hosted from Storage Domain B via Storage Server 2.
>
> We would want to be able to promote Storage Domain B to Master so that
> we can take down Storage Domain A to do maintenance to Storage Server 1.
>
> Once we are done with maintenance to Storage Server 1 we can bring
> Storage Domain A back on line, re-designate it as Master if desired and
> bring it's VM's back online.
>
> I know I have seen this occur automatically to a point when a Storage
> Domain goes missing that is the Master Domain but I have not noted any
> manual method of doing so given the above scenario.
>
> - DHC
>
>
>
>
>
>
>
>
>
> _______________________________________________
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> http://lists.ovirt.org/ mailman/listinfo/users
>
>
> my understanding is you can move the storage domain A which is master to
> maint. engine will promote storage domain B to master and everything should
> continue working as is.
>
>
>
>
>
>       --
>
> Med Vänliga Hälsningar
> -------------------------------------------------------------------------------
> Karli Sjöberg
> Swedish University of Agricultural Sciences
> Box 7079 (Visiting Address Kronåsvägen 8)
> S-750 07 Uppsala, Sweden
> Phone: +46-(0)18-67 15 66
> karli.sjoberg@slu.se
>
>
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