To execute a task that takes 2 minutes every hour, why do you need a B8 with 5 max instances? I don't know what daily quota you're trying to stay within, but if your intention is to stay within 9 hours a day, which costs $0.72, a B5 with 5 instances will exhaust that very quickly. If your two minutes of processing time is mostly spent in I/O - such as datastore operations, cache read/writes, URL fetches, etc, then it'll be a lot more efficient to use a B1 instance. A B8 would only speed up CPU intensive operations, or provide more RAM, if you need it.
Anyways, assuming you need the memory and CPU cycles a B8 provides, you still don't need 5 simultaneous instances to execute a task that takes 2 minutes every hour. I'd recommend tune the instance class to suit your processing needs, but keep the max instance to 1 in bakends.yaml. And a 2 minute job means 17 minutes of instance hour usage every hour (15 minutes standard overhead + 2 minutes task running time), which equals 6.8 hours per day. If you use a B1 backend, you can stay within the daily free quota. The other thing to watch out for is - when you trigger your backend with a cron job, does your task processing spawn other tasks in the task queue? If so, you'll create multiple backends (if allowed in backends.yaml), and even though those multiple simultaneous backends will execute only for a seconds or minutes, you'll incur the 15 minute overhead cost for starting each backend instance. The best way to "smoothen" out the load / processing is to queue up the multiple requests and execute them seriallly on a single backend instance. The best way to accomplish that is to use "Push Queues". You enqueue requests into push queues, and when you dequeue (or "lease") requests one at a time, and execute them one at a time on your backend. Hope this helps. On Wed, Nov 16, 2011 at 11:22 AM, Gerald Tan <[email protected]> wrote: > Each time you shutdown a backend instance, it will continue to be billed > for 15 minutes after. > So if your job takes 2 minutes to run on the backend, you will be billed > for 17 minutes. > B8 instances cost $0.64 for 60 minutes, and your free daily quota is > $0.72, so you will only be able to run for 68 minutes before running out of > quota, which will happen while the 5th hourly job is being shutdown. > > Try using B1 instances, and you'll be fine as long as your job completes > in under 7.5 minutes. > 7.5 + 15 = 22.5 minutes billed per job > 22.5 * 24 / 60 = 9 hours billed per day > 9 * 0.08 = $0.72 billed per day which is your free quota > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/google-appengine/-/__eDHo5o8LQJ. > > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
