Open Stack

On 04/30/2013 11:42 AM, Steve Heistand wrote:
> if I launch one vm at a time its doesnt very long to start up the instance. maybe a minute.
> if I launch 4 instances (of the same snapshot as before) it takes 30 minutes.
>
> they are all launching to different compute nodes, the controllers are all multicore,
> I dont see any processes on the compute nodes taking much cpu power, the controller has
> a keystone process mostly sucking up 1 core, loads and loads of beam.smp from rabbitmq but
> none are really taking any cpu time.
>
> the glance image storage is on the controller node, the snapshots are 2-3G in size.
>
> where should I start looking to find out why things are so slow?

I am something of a "networking guy" so that will color my response :)

Is each  instance using the same image or a different one?  If a 
different one, the "workload" to the glance storage will become (I 
suspect) a random read workload accessing the four different images even 
though each individual stream may be sequential.  How much "storage 
oomph" do you have on/serving the glance/controller node?

After that, what do the network statistics look like?  Starting I 
suppose with the glance/controller node.  Take some snapshots over an 
interval in each case and run them through something like beforeafter:

netstat -s > before
...wait a defined/consistent moment...
netstat -s > after
beforeafter before after > delta

and go from there.

rick jones

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