Greg, can you confirm if a channel in the new pricing scheme is still available for 2 hours and can be reused for multiple clients (as long as they don't overlap in time)?
On Jul 3, 1:39 pm, ksafez216 <mell...@gmail.com> wrote: > You say that the new Channel API rates is what users pay today. > > First of all, in the original model you get over 8,000 free channels a > day to 100/day in the new model. > > And please tell me if 1000's of users are exchanging messages on > individual channels, does that mean that there will be have to 1000's > of instances running at the same time? > > Things should get cheaper and simpler, not more expensive and more > complicated! > > On May 17, 9:49 pm, "Gregory D'alesandre" <gr...@google.com> wrote: > > > > > > > > > Hello All! > > > As you've likely heard, when Google App Engine leaves Preview in the second > > half of 2011, the pricing model will change. Prices are listed > > here:http://www.google.com/enterprise/appengine/appengine_pricing.html. > > But that > > leaves a lot of questions unanswered, this FAQ is intended to help answer > > some of the frequently asked questions about the new model. We are > > interested in hearing additional thoughts and comments you have based on > > this. Once it is relatively stable I'll add it to our official docs. If > > you find there is something you want to know but it is not yet answered, > > just ask and I'll try to answer it as clearly as possible. We've made some > > changes based on the feedback we've gotten (from this group in particular), > > they are bolded below but not updated on the external pages yet. There are > > still blanks to fill in and I will be sending that information to this group > > first in order as it is available. Finally, thank you for your questions > > and bearing with us as we are ironing out details, I and the whole App > > Engine team very much appreciate it. > > > Greg D'Alesandre > > Senior Product Manager, Google App Engine > > > ------------------- > > > *Definitions* > > *Instance*: A small virtual environment to run your code with a reserved > > amount of CPU and Memory. > > *Frontend Instance*: An Instance running your code and scaling dynamically > > based on the incoming requests but limited in how long a request can run. > > *Backend Instance*: An Instance running your code with limited scaling based > > on your settings and potentially starting and stopping based on your > > actions. > > *Scheduler*: Part of the App Engine infrastructure that determines which > > Instance should serve a request including whether or not a new Instance is > > needed. > > > *Serving Infrastructure* > > Q: What’s an Instance? > > A: When App Engine starts running your code it creates a small virtual > > environment to run your code with a reserved amount of CPU and Memory. For > > example if you are running a Java app, we will start a new JVM for you and > > load your code into it. > > > Q: Is an App Engine Instance similar to a VM from infrastructure providers? > > A: Yes and no, they both have a set amount of CPU and Memory allocated to > > them, but GAE instances don’t have the overhead of operating systems or > > other applications running, so a much larger percentage of the CPU and > > memory is considered “usable.” They also operate against high-level APIs and > > not down through layers of code to virtual device drivers, so it’s more > > efficient, and allows all the services to be fully managed. > > > Q: How does GAE determine the number of Frontend Instances to run? > > A: For each new request, the Scheduler decides whether there is an available > > Instance for the request, the request should wait, or a new Instance should > > be created to service the request. It looks at the number of Instances, the > > throughput of the Instances, and the number of requests waiting. Based on > > that it predicts how long it will take before it can serve the request (aka > > the Pending Latency). If it predicts the delay will be over 1 second, a new > > Instance is created. If it looks like an Instance is no longer needed, it > > will take that Instance down. > > > Q: Should I assume I will be charged for the number of Instances currently > > being shown in the Admin console? > > A: No, we are working to change the Scheduler to optimize the utilization of > > instances, so that number should go down somewhat. If you are using Java, > > you can also make your app threadsafe and take advantage of handling > > concurrent requests. You can look at that as an upper bound on how many > > Instances you will be charged for. > > > Q: How can I control the number of instances running? > > A: With the new Scheduler you’ll have the ability to choose a set of > > parameters that will help you specify how many instances are spun up to > > serve your traffic. More information about the specific parameters and how > > they will affect the Scheduler will be available on this within a few weeks. > > > Q: What can I control in terms of how many requests an Instance can handle? > > A: The single largest factor is your application’s latency in handling the > > request. If you service requests quickly, a single instance can handle a > > lot of requests. Also, Java apps support concurrent > > requests<http://code.google.com/appengine/docs/java/config/appconfig.html#Usin...>, > > so it can handle additional requests while waiting for other requests to > > complete. This can significantly lower the number of Instances your app > > requires. > > > Q: Will there be a solution for Python concurrency? Will this require any > > code changes? > > Python concurrency will be handled by our release of Python 2.7 on App > > Engine. We’ve heard a lot of feedback from our Python users who are worried > > that the incentive is to move to Java because of its support for concurrent > > requests, so we’ve made a change to the new pricing to account for > > that. *While > > Python 2.7 support is currently in progress it is not yet done so we will be > > providing a half-sized instance for Python (at half the price) until Python > > 2.7 is released.* > > > Q: How many requests can an average instance handle? > > A: Single-threaded Instances (python or java) can currently handle 1 > > concurrent request. Single-threaded Instances (python or java) can > > currently handle 1 concurrent request. Therefore there is a direct > > relationship between the latency and number of requests which can be handled > > on the instance per second, for instance: 10ms latency = 100 > > request/second/Instance, 100ms latency = 10 request/second/Instance, etc. > > Multi-Threaded Instances can handle many concurrent requests. Therefore > > there is a direct relationship between the cpu consumed and the number of > > requests/second. For instance, for a B4 (approx 2.4GHz) instance: consuming > > 10 Mcycles/request = 240 request/second/Instance, 100 Mcycles/request = 24 > > request/second/Instance, etc. These numbers are the ideal case but they are > > pretty close to what you should be able to accomplish on an Instance. > > Multi-Threaded instances are currently only supported for Java; we are > > planning support for Python later this year. > > > Q: Why is Google charging for instances rather than CPU as in the old model? > > Were customers really asking for this? > > A: CPU time only accounts for a portion of the resources used by App Engine. > > When App Engine runs your code it creates an Instance, this is a maximum > > amount of CPU and Memory that can be used for running a set of your code. > > Even if the CPU is not currently working due to waiting for responses, the > > instance is still resident and considered “in use” so, essentially, it still > > costs Google money. Under the current model, apps that have high latency > > (or in other words stay resident for long periods of time without doing > > anything) are not able to scale because it would be cost-prohibitive to > > Google. So, this change is designed to allow developers to run any sort of > > application they would like but pay for all of the resources that are being > > used. > > > Q: What does this mean for existing customers? > > A: Many customers have optimized for low CPU usage to keep bills low, but in > > turn are often using a large amount of memory (by having high latency > > applications). This new model will encourage low latency applications even > > if it means using larger amounts of CPU. > > > Q: How will always-on work under the new model? > > A: Still determining how this will work, answer coming very soon (no > > seriously, we are almost done). > > > Q: What is the difference between On-demand Instances and Reserved > > Instances? > > A: On-demand Instances have no pre-commitment in terms of the number that > > will be used. You pay for them as you use them. Reserved Instances are > > pre-commitment to a certain number of Instance Hours in a week. They are > > cheaper but you must pay for all the Instance Hours that you have > > pre-committed to whether you use them or not. This does not mean they have > > to be running the whole time. > > > Q: Wait, so Reserved instances don’t mean you have to keep them running the > > whole time? > > A: No, it is just a way to get cheaper instance-hours by pre-committing to > > them. > > > Q: What is the time granularity of the instance pricing? ie if I have an > > instance up for 5 minutes, what am I charged, $0.08 / 60*5? > > A: Instances are charged for their uptime and until they are idle for 15 > > minutes (when the scheduler takes them down). So if you have an on-demand > > Instance only serving traffic for 5 minutes, you will pay for 5+15 minutes, > > or $0.08 / 60 * 20 = 2.6 cents. > > > Q: You seem to be trying to account for RAM in the new model. Will I be > > able to purchase Frontend Instances that use different amounts of memory? > > A: We are only planning on having one size of Frontend Instance. > > > Q: Do Frontend instances handle Task Queues and Cron? > > A: Yes. > > > Q: Can the experimental Go Runtime handle concurrent requests? > > A: Not currently. > > > *Costs* > > Q: Is the $9/app/month a fee or a minimum spend? > > A: *Based on the feedback we’ve received we are changing this $9 fee to be a > > minimum... > > read more » -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
