How to limit the number of instances UpStart can simultaneously start or respawn

Question

I have a UpStart service job that has many (~100) instance that need to be started. Each of them is a resource-heavy process that does a lot of disk reading/writing during startup. When all of them start or respawn at the same time, they cause trouble due to excessive disk read/write requests.

I need a way to limit the number of instances that UpStart tries to start or respawn simultaneously. For example, is there a way to let UpStart hold off launching another instance until, say 30 seconds, after the startup or respawning of another instance has begun?

Answer 1

You can start them in sequence by using

start on started otherUpstartService

Answer 2

You can use pre-start or post-stop to pause after each job. E.g post-stop exec sleep 5