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Re: [nova] [cinder] Nova-volume vs. Cinder in Folsom

 

+1 for 1

On 11/07/12 8:26 AM, "Vishvananda Ishaya" <vishvananda@xxxxxxxxx> wrote:

>Hello Everyone,
>
>Now that the PPB has decided to promote Cinder to core for the Folsom
>release, we need to decide what happens to the existing Nova Volume
>code. As far as I can see it there are two basic strategies. I'm going
>to give an overview of each here:
>
>Option 1 -- Remove Nova Volume
>==============================
>
>Process
>-------
> * Remove all nova-volume code from the nova project
> * Leave the existing nova-volume database upgrades and tables in
>   place for Folsom to allow for migration
> * Provide a simple script in cinder to copy data from the nova
>   database to the cinder database (The schema for the tables in
>   cinder are equivalent to the current nova tables)
> * Work with package maintainers to provide a package based upgrade
>   from nova-volume packages to cinder packages
> * Remove the db tables immediately after Folsom
>
>Disadvantages
>-------------
> * Forces deployments to go through the process of migrating to cinder
>   if they want to use volumes in the Folsom release
>
>Option 2 -- Deprecate Nova Volume
>=================================
>
>Process
>-------
> * Mark the nova-volume code deprecated but leave it in the project
>   for the folsom release
> * Provide a migration path at folsom
> * Backport bugfixes to nova-volume throughout the G-cycle
> * Provide a second migration path at G
> * Package maintainers can decide when to migrate to cinder
>
>Disadvantages
>-------------
> * Extra maintenance effort
> * More confusion about storage in openstack
> * More complicated upgrade paths need to be supported
>
>Personally I think Option 1 is a much more manageable strategy because
>the volume code doesn't get a whole lot of attention. I want to keep
>things simple and clean with one deployment strategy. My opinion is that
>if we choose option 2 we will be sacrificing significant feature
>development in G in order to continue to maintain nova-volume for another
>release.
>
>But we really need to know if this is going to cause major pain to
>existing
>deployments out there. If it causes a bad experience for deployers we
>need to take our medicine and go with option 2. Keep in mind that it
>shouldn't make any difference to end users whether cinder or nova-volume
>is being used. The current nova-client can use either one.
>
>Vish
>
>
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