Because the scheduler is now treating the reserved instances as Min-Idle-Instances, what you're describing is expected behavior. They are intentionally kept idle, and it tries to serve traffic using the non-reserved instances. Then, if the non-reserved instances can't keep up, then it will make use of the reserved instances.
That is, to repeat, the invariant that the scheduler is trying to maintain here is that your app has at least 3 idle instances. And if an instance is getting traffic, then it isn't idle. The value of an idle instance is that it can process requests right-away if needed, without having to first warmup or do a loading request. It sounds like what you'd really prefer is something like Min-Instances, but that's not presently an available option. If you set Max-Idle-Instances, then you will never be charged for any instances which are idle in excess of the configured value. In this example, if Max-Idle-Instances=3, and the scheduler is running 6 instances, and three of them are always idle, then the resulting charge would be for 3 instances. On Thu, Jul 28, 2011 at 1:49 PM, Mike Lawrence <[email protected]> wrote: > Just ran a volume test on my server. > The three reserved instances are not getting any traffic. > That can't be normal. > Instead GAE spawned 3 dynamic instances to handle all the load. > I have set Max Idle instances to 3. > Why would you ever want instances to sit idle under a load test? > If you have capacity (idle instances), why not use them when you're > under heavy load? > http://dl.dropbox.com/u/473572/Untitled2.jpg > Wouldn't I be charged for 6 instance under the new pricing model when > I'm only really using 3? > > > On Jul 27, 7:12 pm, Jon McAlister <[email protected]> wrote: >> So, there's a couple of things going on here. I'll see if I can help explain. >> >> The first is that with 1.5.2 we changed how resident instances work, >> so that if a dynamic instance existed, the scheduler would prefer an >> idle dynamic instance to an idle resident instance. Further, if a >> resident instance was busy, we would use this as a cue to warmup a new >> dynamic instance. The point of these changes is to turn the resident >> instances into the reserve for the app. They are generally idle, but >> if the app gets more traffic than it can handle with non-reserved >> instances, then it will use some of the reserved instances (and this >> will in turn spawn a new dynamic instance). >> >> Generally, Always On is going away with the new billing plan, and >> being replaced by Min Idle Instances, which is how the reserved >> instances have been changed to behave with 1.5.2. We're continuing to >> evaluate all aspects here, both how well these reserve instances are >> working, what we should be doing, what we should change about the >> scheduler and the billing plan, and so on. >> >> In terms of this specific example, the slow request was caused by >> general bigtable slowness during that time interval. This can be seen >> somewhat >> here:http://code.google.com/status/appengine/detail/datastore/2011/07/27#a... >> >> This can also be investigated somewhat using our logs viewer. For >> example, we can see all loading requests for an app >> with:https://appengine.google.com/logs?app_id=wordpong&severity_level_over.... >> Note how the only loading requests this app has received have been >> /_ah/warmup >> >> Also we can see all requests sent to a specific instance. Here's the >> one with the log line you listed >> above:https://appengine.google.com/logs?app_id=wordpong&severity_level_over.... >> Note how the first request the instance served was /_ah/warmup, >> followed by a pause of 4 seconds, followed by the /game/Game.wp >> request which ran for 9 seconds. >> >> There are a couple of things that can be done now to get different >> behaviors. One is to set Max Idle Instances to three, which will kill >> off the dynamic instances for your app, and leave the app with just >> the resident instances. The other is to use Backends, which will give >> you direct control over how many instances run for your app and their >> properties:http://code.google.com/appengine/docs/java/backends/overview.html >> >> Hopefully that helps. There is also a lengthy discussion going on >> at:http://groups.google.com/group/google-appengine/browse_thread/thread/... >> >> >> >> >> >> >> >> On Wed, Jul 27, 2011 at 2:59 PM, Mike Lawrence <[email protected]> >> wrote: >> > I purchased 3 Always-On instances. >> > My site is under construction with no traffic. >> > When I hit my site, GAE fires up a new dynamic instance to service the >> > request when there are 3 idle instances! >> > My app starts in 2.0 seconds (using stripes) >> > But GAE takes 9.4 seconds to reply (why?). >> > Really annoying. >> > Why pay for Always-On when you get the crappy response time of dynamic >> > instances? >> >> > App Id: WordPong >> >> > EST: >> > 2011-07-27 17:37:04.859 /game/Game.wp?_eventName=questionList 200 >> > 9481ms 2063cpu_ms 103api_cpu_ms 1kb Mozilla/5 >> > 2011-07-27 12:37:51 Completed update of a new default version >> > version=22.2011-07-27T19:37:17Z >> >> > Here's the screen shot of my instances at the time of the request: >> >http://dl.dropbox.com/u/473572/Untitled.jpg >> >> > Why are there any dynamic instances running at all when there are 3 >> > idle always-on instances available? >> > Looks like a serious bug where GAE is wasting resources and providing >> > poor response times for no reason. >> >> > -- >> > 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 >> > athttp://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. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. 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