About scaling XAF ASP.NET applications

Thanks Denis,
I do understand that providing specs would be difficult if the complexity of the app is not known. As in my case, i have tried to tap to the memory usage and it is roughly taking up 60MB and i have tried it with 5 users in our development environment and everything seems to work fine and the memory usage is fluctuating between 80 to 100 MB (on 5 concurrent user requests).
In our case we have recommend the server hardware to have at least 4 Mb RAM. But what is not clear to us is the CPU speed. Could you please throw some light on it.
I haven't deployed the app on cloud yet but was getting prepared for our future project hence i asked the question. I have spent over 1 year working on XAF (time & money) and would be difficult to switch to others and i guess XAF community is a large community and you guys will take Scaling XAF applications to high priority.
Regarding sticky sessions i haven't experienced it yet but while preparing for our future project i have come across it and it looks like there are quite a lot of limitations (like the web request stays with one server only and if the server fails then the session is lost, session is maintain at physical server level which means the server will serve for the whole life cycle of the request/user while there may be other servers idle.)
All what i am looking is for the future scalability as the demand grows and we have to be ready.

By the way, below is the code i am using to get the memory usage of the application.
As i have hosted my application on a public domain and I don't have access to OS level of tools to know the memory,  I am using this technique to get an idea about the memory used by the application.
Private Sub btnGetMemoryUsage_Execute(sender As Object, e As SimpleActionExecuteEventArgs) Handles btnGetMemoryUsage.Execute
       Dim bytes As Long = GC.GetTotalMemory(False) / 1000000
       Throw New UserFriendlyException("Memory usage is " & bytes.ToString & " MB")
   End Sub

Thanks for your update, Mohammed. As I mentioned above, I wish, but I cannot shed light on the CPU spec which will be sufficient in your particular case. This is to be determined by you through testing under the conditions similar to the production ones (users' load, environment, etc.)  and not with just five users on your development machine.

Thanks for answering my question about practical deployment experience. Once you have a real opportunity to practically deploy and test your XAF web site, it would be great to hear of your experience.
While, in my opinion, checking these aspects is important during the evaluation period when determining whether a tool is good for your business needs or not, we will take your feedback on the planned number of concurrent users into account for the future. We are already monitoring such requests and, to be honest, there are not many users who contacted us about this as compared to other feature requests (e.g., requests for the new Web UI style or mobile client). Probably, because the needs of the majority of clients can already be meet with a single VM in the Cloud (e.g., because their typical apps are simple Intranet portals or backoffices/administrative UIs fort the public non-XAF web clients) or with "sticky" session solutions. Regardless, our team appreciates and understands your input in this regard.

As for using other tools to some moment, I want to say that while it would be great to have one tool to handle all requirements, it is difficult or impossible in the real world so that user expectations in each scenario are met at the high level… it's like creating a fast race car that would also be a good SUV and a comfortable sedan at the same time - this is a nice wish, but is not ever possible. I have updated my answer in the XAF ASP.NET Web Forms apps deployment considerations ticket accordingly. I hope I explained my point well.

Mohammed, since the request is pending for 5++, i don't think they will do it. same as you, when i first saw 'Web', my first in mind is 'open' to anyone can use it, when we 'open', means number of user are unknown. When user growth, we have NLB, server is not an issue, you have money to buy it, you just tell me how many user you want to use.
come back to XAF, you need to change mind, it is not open to anyone, you need to be careful of the number of user, when it growth ( of course, unless our customer close shop ), you prepare to switch to other tools. In terms of application type, you need to scope it limit to inhouse use only, in my opinion, might be like Employee leave application, Name Card system will be suitable. Payroll or account system will also good in this case but for account, if you open your 'Purchase Order' to public, you will be trouble since you will not know the number of user will login to your XAF Web to place order. You might need to use other tools to create a separate 'PO Web' for your customer.
nothing wrong with XAF, at the very beginning time and documentation, they have clearly state there the XAF is suitable for inhouse application, actually is my fault to overlook this at the beginning.
I only realize when my customer told me he need to open some of the module to his's customer and due to the number of concurrent user will be around 1K++ ( estimate ), his network team planing to do NLB and ask me to assists on it. From that time onward, i start look at the XAF NLB and realize there is something which is not my expect.
Anywhere, since we still can use sticky session, it is better than nothing. And i will also try to talk to them using mobile web for outside customer. This is my last 2 option, if still cannot, i will give up and ask him to look for other vendor.
Hopefully Dennis will not angry on me. If anything offend, please forgive.
Thanks.