[openstack-dev] [nova] Migration progress

Jay Pipes jaypipes at gmail.com
Sun Feb 7 19:31:09 UTC 2016

On 02/04/2016 11:02 PM, Bhandaru, Malini K wrote:
> Another thought, for such ephemeral/changing data, such as progress,
> why not save the information in the cache (and flush to database at a
> lower rate), and retrieve for display to active listeners/UI from the
> cache. Once complete or aborted, of course flush the cache.
> Also should we provide a "verbose flag", that is only capture
> progress information when requested? That is when a human user might
> be issuing the command from the cli or GUI tool.

I agree with you, Malini, on the above suggestion that there is some 
doubt as to the value of saving this temporal data to the database.

Why not just have an on-demand model that simply routes the request for 
progress information directly to the compute node and sends the progress 
amount back directly to the nova-api service instead of going to the 
database at all?

Another alternative would be to use a push model instead of a poll 
model, but that would require a pretty significant change to the code...


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