openstack team mailing list archive

[Chuck Short <chuck.short@xxxxxxxxxxxxx>]

On Wed, 11 Jul 2012 08:26:56 -0700
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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