A simple calculation
Monday, February 14, 2011
11:18 AM
Suppose we're sampling performance at some fixed interval Δt. 
Suppose we know the maximum rate at which P can increase; call that M = max(ΔP/Δt). 
Suppose that it takes us time tdeploy to deploy a new instance. 
Let N=  tdeploy/Δt  where  A  is the least integer greater than A. 
This is the number of update cycles it takes to deploy an instance. N can vary between 1 (pre-deployed virtual instance) and several hundred (need to install an instance). 
Then it had better be that P+NM < PSLA.
Otherwise, the new instance has been deployed too late to help!