On Thu, Sep 8, 2011 at 10:37 AM, Jon McAlister <[email protected]> wrote: > > Hi Joshua, > You are right, I should have been more explicit. While I believe > what I said to be true for most apps, you are right that there > exists classes of apps where the second half of the billing > formula needs to be explicitly considered. > For your app towngovernment, it has one instance serving pretty > much all day, and occasionally two. The > active-instances-rate (the orange line) is always <0.1, and the > total-instances-rate (the blue line) is 1 and occasionally 2. You > have set max-idle-instances=1. As such, with the billing formula: > billable-instances-rate = min(active-instances-rate + max-idle-instances, > total-instances-rate) > This evaluates to billable-instances-rate = min([0..0.1] + 1, > [1..2]) = [1..1.1]. That is, it has a different value at each > part of the day depending on the present value of > active-instances or total-instances, but always lays in the range > [1..1.1]. > Further, since you set max-idle-instances=1 at > 2011/09/06-06:50:41, what I said above only really applies to > your billing reports for 09-06 and onwards. Although, for the > 09-06 report, it only applies to 17/24 of the day, whereas for > the 09-07 report it will apply to the entire day. Note that this > is actually why your 09-06 billable instances hours (25.59) are > less than your 09-06 billable instance hours (29.17). Also, your > 09-07 report should be even lower.
Oops, a typo. I meant to say: """Note that this is actually why your 09-06 billable instances hours (25.59) are less than your 09-05 billable instance hours (29.17). Also, your 09-07 report should be even lower.""" > I think that 25 daily instance hours is about the lowest your > going to see for this app. > I hope that helps, > Jon > > On Thu, Sep 8, 2011 at 8:45 AM, Joshua Smith <[email protected]> wrote: >> >> On Sep 8, 2011, at 10:36 AM, Jon McAlister wrote: >> >> I thought I did respond... In any event, for the reasons you listed >> above and others, this is why max-idle-instances is important. It >> ensures that you are not held accountable for scheduler behaviors such >> as these listed. When you set it, the billable-instances-rate is >> determined by max-idle-instances (a setting you directly control) and >> active-instances-rate (again, hopefully something you control). The >> nuances of how the scheduler spins up extra instances to minimize >> latency and provide spare capacity are not part of the formula, other >> than their effect on your serving latency and reliability. >> >> Unless I'm misunderstanding, we are "held accountable for scheduler >> behaviors such as these listed." >> If the load could be served by a single instance, but the scheduler decides >> to start a second one to handle a single request (for no apparent reason), >> there is going to be a minimum of 0.25 instance hours added to my bill. If >> this happens once a day, and I need an instance up all the time to handle an >> external kiosk which refreshes itself, then I'm going to be charged for >> 24.25 - 24 (free) = 0.25 instance hours. If this happens X times a day, >> I'll be charged for 0.25X instance hours a day. And I have the billing >> prediction numbers to prove it: >> >> Obviously, this isn't that big a deal, since I've got to give you $9 a month >> anyway. But if the weird scheduler behaviors scale up, then this occasional >> propensity to start unneeded instances could really start costing someone >> some serious $$. >> -Joshua >> >> -- >> 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. > -- 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.
