Thanks Prasad,
Makes sense that the project page goes up AFTER it is
approved.
-ashu
Prasad Dharmavaram wrote:
> Ashu,
>
> Once the project gets the approval by the community leaders then it
> will be sent to one of the opensolaris leaders who will create
> a project page. From then on all the project documents can be
> put in that web page.
>
> e.g: you can see the HA-Informix community page here
>
> http://opensolaris.org/os/project/ha-informix
>
> Neil can add all this discussion later when the project page
> is available.
>
> --prasad
>
> Ashutosh Tripathi wrote:
>> Hi Neil,
>>
>> Very cool. Glad that i asked about the "lesser DomUs being
>> offlined" thingie because, as you can see, i was taking it as
>> a completely different beast then what you had in mind.
>>
>> Vote approval.
>>
>> PS: For others in the community who might have similar questions such as
>> mine, is there a way to deposit a more detailed description of the
>> project somewhere on the community site? I didn't see a URL for this
>> proposed project anywhere in this e-mail thread, which leads me to
>> believe that this project exists only in this thread so far.
>>
>> Thanks,
>> -ashu
>>
>>
>> Neil Garthwaite wrote:
>>> Hi Ashu,
>>>
>>> Concerning migration it would be triggered by a "clrg switch" command,
>>> although migration or live migration would be resource specific. By this I
>>> mean that when a "DomU resource" is registered with OHAC, the switchover
>>> method will be determined, i.e. migration, live migration or just failover
>>> (stop/relocate/start). However whatever method is chosen, the appropriate
>>> method would be triggered by a "clrg switch" and implemented by the HA-Xen
>>> agent.
>>>
>>> There are some restrictions for migration, in that the DomU's virtual block
>>> devices (VBD) need to be accessible by both nodes that are participating in
>>> such a migration. One could think of "accessible" in terms of a global file
>>> system. If a Zpool/ZFS was being used by a DomU's VBD list, then that
>>> Zpool/ZFS would only be available to both nodes participating in a
>>> migration and not accessible. In this regard, it's my belief that migration
>>> or live migration would not be possible for a DomU using a Zpool/ZFS VBD.
>>> However, my belief my change once we are engaged with the Xen community.
>>>
>>> Concerning placing a DomU offline. For those familiar with Solaris Cluster,
>>> this is akin to RG_affinities and in particular a strong negative affinity.
>>> For those not familiar with this terminology please see
>>> http://blogs.sun.com/SC/entry/how_does_sun_cluster_decide for an
>>> informative article about affinities.
>>>
>>> With the above in mind, "Allow for important DomUs where lesser DomUs are
>>> "offlined" means that using HA-Xen with OHAC and assuming a 2-node cluster,
>>> under normal operations both nodes could be running several domUs. However,
>>> some DomUs maybe more important than others and in the event of a node
>>> failure it maybe desirable to favor an important DomU over another DomU.
>>>
>>> Utilizing RG_affinities it would be possible to offline a less important
>>> DomU in favor or an important DomU to free up system resources so that upon
>>> failover the important DomU maintains a specific service level.
>>>
>>> In summary, this is an important feature and one that already exists within
>>> Solaris Cluster and therefore OHAC. However, in my opinion perhaps the
>>> greatest strength of RG_affinities is the knowledge that one could utilize
>>> all nodes thereby not having any idle nodes with the comfort of knowing
>>> that in the event of a node failure, OHAC + HA-Xen will favor important
>>> DomUs over lesser DomUs when using RG_affinities.
>>>
>>> Many thanks for your support with the remainder.
>>>
>>> Regards
>>> Neil
>>> --
>>>
>>> This message posted from opensolaris.org
>>>
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