[Users] Designate Master Storage Domain
Itamar Heim
iheim at redhat.com
Sat Aug 17 06:50:03 UTC 2013
On 08/16/2013 04:46 PM, Dead Horse wrote:
> 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 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.
>
I'm sorry - how is pausing VMs running from a storage domain moved to
maint is related to master storage domain?
> - DHC
>
>
> On Fri, Aug 16, 2013 at 12:14 AM, Karli Sjöberg <Karli.Sjoberg at slu.se
> <mailto:Karli.Sjoberg at 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 at redhat.com
>> <mailto:iheim at 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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>>
>>
>> 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 <tel:%2B46-%280%2918-67%2015%2066>
> karli.sjoberg at slu.se <mailto:karli.sjoberg at adm.slu.se>
>
>
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