DotNetNuke Scalability - scalability

We are about to start in a content-rich web site and we are considering Dotnetnuke.
The site will be multilingual with size compared to that of the UN site (http://www.un.org/en/index.shtml )
The question is: Would DotNetNuke support such large content size? is there a limit on the size of content or the depth of the hierarchy?

DotNetNuke is very scalable, but as with any application you need to be considerate of the hardware you have things running on. Proper planning up front will help you to alleviate any potential load issues.
As for content and the depth of content, portals, pages, modules, you can create as much depth as is necessary, keeping in mind the hierarchy of content can lead to potential concerns about ease of management of that content.

In our company we run about 50 instances with over 150 portals in DotNetNuke. Some of them have lots of content with lots of user (>100000 users). So far we never had a problem with any of them in terms of performance. I don't know of any limitations regards content depth or similar.

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System architecture advice for a dual interface online/mobile marketplace

My startup is building an online/mobile labor marketplace where there will be a business interface for businesses posting jobs and we distribute these jobs through a mobile interface for users. We use Rails, REST, Amazon RDS & EC2 and mysql.
My question is: from an architecture standpoint on the server-side does it make sense to?:
a) Have 2 applications one serving the web interface and one acting as the server-side (API) for the mobile interface and both communicating via the DB and via 2 different EC2 instances
b) Try to build one comprehensive application serving both interfaces
Any opinion and perspective on pros and cons would be much appreciated
Thanks
Amazon Web Services are giving you a few tools to make your architecture simpler, more robust and scalable, if you break down your system into smaller, simpler and independent components.
Since you have a set different sizes of instances from micro to extra large (and a few sizes of extra large), you have the flexibility to mix each service type to the appropriate size, configuration, software dependencies, update cycle etc. It will make the life of the developers, testers and administrators much easier.
You also have the ability to scale and even auto-scale each layer and service independently. If you have more users of one of the interfaces, or the other, or increase in data size that is fed through one of the interfaces, you can scale only the relevant service. It will save you the complexity and cost of scaling the full system as a whole.
Another characteristic of AWS is the ability to scale up, down, out and in based on your need. For example, if one of the interface has more users on working weekdays and fewer on weekends, you can scale down this interface for the weekend or night, saving 50% of your computation costs for this instances. In this regards, you can switch from the on-demand model for the more static interfaces to reserved instances, saving again 50% of your costs.
To allow communication between the different interfaces you can use your DB, but you also have a few more options based on your use case. One option is to use Queueing system as SQS. The queue is used as a buffer between the interfaces, reducing the risk of failure of one component (software bug, hardware failure...), affecting the whole system. Another option for inter interfaces communication, that is more tuned to performance is to use in-memory cache. AWS are offering ElasticCache as such service. It can be more efficient than updating such transient data for short period of time and with high load.
I see no long term cons, other than the quick (and dirty) implementation of a single service on a single machine.
The overall goal should be to have most amount of code common between the mobile and web application. Otherwise you are looking at maintenance headaches where you will end up e.g. fixing bugs, or adding features at two places at minimum.
Ideally everything below the front end should be common. The web UI should itself be calling the server side APIs that you are going to need for mobile application. And most amount of logic should be put into these APIs, leaving only presentation details to the UI. This is as prescribed by many patterns such as MVC.
I have a mobile site and desktop site running myself. The codebase is exactly the same at PHP level. Only the smarty templates are different between the two. Granted that mobile application is different from mobile site, but the basic principles still apply.

Is JSP not a good choice as a server side scripting language for consumer-scale multinational portals? e.g. for Facebook/Gmail scale or beyond?

The site/app would be AJAX heavy and will have UI MashUps. Would using an AJAX toolkit or lot of Javascript in the webpage go against scale goals, in other words, would more bandwidth consumption due to Javascript-heaviness would affect bottomline?
Sorry to ask two questions together, somehow they are related to overall SCALE goal at client tier.
Thanks in advance,
Deb
Sorry, but your question is unclear.
You first ask about JSP being a good choice, then talk about scalability. The two must be treated separately.
JSP is a server-side platform, just as PHP and ASP.NET. According only to the design of your web application, it's perfectly scalable. Actually, you can choose any of the listed platforms if your goal is scalability, plus a little more hints.
Second, Javascript and bandwidth consumption. If you have a good (and I mean good) AJAX toolkit, then I suppose lots of JS contents are static. I mean lots of functions and class libraries are stored in static JS file that don't change during software's lifetime, and that's exactly what we want!! The only part that change is the page-level scripting and the XMLHTTP responses.
Now, all the libraries can be cached by browsers, dramatically reducing bandwidth consumption.
My hint
is to use a static content domain, possibly powered by a Content Distribution Network.
This will unload a lot your JSP-busy servers on a scalable application.
Remember
Your web application must be correctly designed to be scalable (don't rely on session variables, for example)

Single technology stack vs. multiple technologies for high scale site

I have recently been come to for advise on an idea of rewriting an existing site due to massive maintenance problems in their old design.
Basically, the company is considering a complete rewrite of aprox. 90% of their site which is currently written in PHP using an in-house framework.
The company would like to rebuild the backend and some way down the road the front-end as well in order to minimize their maintenance problems and make it easier to bring in new tallent which doesn't need to spend months learning the architecture before they can become affective developers.
We've come up with several possible architectures, some involving rewriting the whole site using an existing scripting web framework such as Cake, Django or RoR and some compiled language frameworks in Java or even .Net.
In addition we have come up with some cross technology solutions - such as a web application built in Django with a Scala backend.
I was wondering what merit would there be to using a single technology stack (such as RoR) as apposed to using a cross between two (such as RoR with Scala, like Twitter now do) and vise versus.
Take into consideration the fact that this company's site is a high traffic site with over 1 million unique visitors a day, which will be transitioned onto the new architecture slowly over a long period (several month to a year)...
Thanks
Generally speaking, I don't think any particular technology stack is better than any other in terms of performance; Facebook runs on PHP and I know first hand that Java and .Net scale well too. Based on what you've said I'd be worrying more about the maintainability related issues than performance and scalability just now.
Generally speaking, I would keep within one well known technology stack if possible:
It'll be easier to find (good) staff for a well known platform / technology stack; there will be more in the market, and rates will not be as expensive as the skills are too rare.
Splitting your technology means you need a wider range of knowledge; by sticking with a single technology stack you can focus on it, with better / faster results.
People tend to focus on one platform / technology stack, so it'll be easier to find developers for technology X, rather than technologies X, Y and Z.
It's easier for team members to work on different parts of the system as it's all written in the same technology - presumably in a similar way.
In terms of integation, items within the same technology stack play nicer together, crossing into different stacks can quickly become more difficult and harder to support.
Where you do want to use different technology, ensure the boundary is clean - something standards based or technology agnostic like web service / JSON calls.
Rewriting your whole codebase will require significant effort and lots of pressure, and for a start you would be best to start by doubling or maybe tripling the initial time estimate.
You can think about your problem from two perspectives :
Number of platforms. In order to minimize and manage complexity of this task, it is most definitely your imperative to reduce mental strain by using as less new technologies/platforms as possible. For example, an advantage of RoR over PHP+Smarty that has been cited often is that with RoR you don't have to learn a new presentation language.
Team effort required to learn new techs. If your existing team is already versatile with PHP, Django etc, but not RoR, then you might be better off reusing existing skills, since the mental strain for developers will be lesser.
Single technology means less moving targets; simpler is always better as long as it meets the requirements. So, use as many technologies as you need, but not more than that. The technology is not important; the right technology is the one that makes your job easier. So, ask yourself what are your current pain points, and how would each of those technologies help.
Getting the architecture right and the code clean is the easiest with Smalltalk and Seaside, especially when you do the persistence with Gemstone. At this scale, you'll have to talk to them about license costs. You might know them from the Ruby work they do with Maglev.

What really is scaling?

I've heard that people say that they've made a scalable web application..
What really is scaling?
What can be done by developers to make their application scalable?
What are the factors that are looked after by developers during scaling?
Any tips and tricks about scaling web applications with asp.net and sql server...
What really is scaling?
Scaling is the increasing in capacity and/or usage of your application.
What do developers do to make their application scalable?
Either allow their applications to scale vertically or horizontally.
Horizontal scaling is about doing things in parallel.
Vertical scaling is about doing things faster. This typically means more powerful hardware.
Often when people talk about horizontal scalability the ideal is to have (near-)linear scalability. This means that if one $5k production box can handle 2,000 concurrent users then adding 4 more should handle 10,000 concurrent users. The closer it is to that figure the better.
The ideal for highly scalable apps is to have near-limitless near-linear horizontal scalability such that you can just plug in another box and your capacity increases by an expected amount with little or no diminishing returns.
Ideally redundancy is part of the equation too but that's typically a separate issue.
The poster child for this kind of scalability is, of course, Google.
What are the factors that are looked after by developers during scaling?
How much scale should be planned for? There's no point spending time and money on a problem you'll never have;
Is it possible and/or economical to scale vertically? This is the preferred option as it is typically much, much cheaper (in the short term);
Is it worth the (often significant) cost to enable your application to scale horizontally? Distributed/multithreaded apps are significantly more difficult and expensive to write.
Any tips and tricks about scaling web applications...
Yes:
Don't worry about problems you'll never have;
Don't worry much about problems you're unlikely to have. Chances are things will have changed long before you have them;
Don't be afraid to throw away code and start again. Having automated tests makes this far easier; and
Think in terms of developer time being expensive.
(4) is a key point. You might have a poorly written app that will require $20,000 of hardware to essentially fix. Nowadays $20,000 buys a lot of power (64+GB of RAM, 4 quad core CPUs, etc), probably more than 99% of people will ever need. Is it cheaper just to do that or spend 6 months rewriting and debugging a new app to make it faster?
It's easily the first option.
So I'll add another item to my list: be pragmatic.
My 2c definition of "scalable" is a system whose throughput grows linearly (or at least predictably) with resources. Add a machine and get 2x throughput. Add another machine and get 3x throughput. Or, move from a 2p machine to a 4p machine, and get 2x throughput.
It rarely works linearly, but a well-designed system can approach linear scalability. Add $1 of HW and get 1 unit worth of additional performance.
This is important in web apps because the potential user base is ~1b people.
Contention for resources within the app, when it is subjected to many concurrent requests, is what causes scalability to suffer. The end result of such a system is that no matter how much hardware you use, you cannot get it to deliver more throughput. It "tops out". The HW-cost versus performance curve goes asymptotic.
For example, if there's a single app-wide in-memory structure that needs to be updated for each web transaction or interaction, that structure will become a bottleneck, and will limit scalability of the app. Adding more CPUs or more memory or (maybe) more machines won't help increase throughput - you will still have requests lining up to lock that structure.
Often in a transactional app, the bottleneck is the database, or a particular table in the database.
What really is scaling?
Scaling means accommodating increases in usage and data volume, and ideally the implementation should be maintainable.
What developers do to make their application scalable?
Use a database, but cache as much as possible while accommodating user experience (possibly in the session).
Any tips and tricks about scaling web applications...
There are lots, but it depends on the implementation. What programming language(s), what database, etc. The question needs to be refined.
Scalable means that your app is prepared for (and capable of handling) future growth. It can handle higher traffic, more activity, etc. Making your site more scalable can entail various things. You may work on storing more in cache, rather than querying the database(s) unnecessarily. It may entail writing better queries, to keep connections to a minimum, and resources freed up.
Resources:
Seattle Conference on Scalability (Video)
Improving .NET Application Performance and Scalability (Video)
Writing Scalable Applications with PHP
Scalability, on Wikipedia
Books have been written on this topic. An excellent one which targets internet applications but describes principles and practices that can be applied in any development effort is Scalable Internet Architectures
May I suggest a "User-Centric" definition;
Scalable applications provide a consistent level of experience to each user irrespective of the number of users.
For web applications this means 24/7 anywhere in the world. However, given the diversity of the available bandwidth around the world and developer's lack of control over its performance and availability, we may re-define it as follows:
Scalable web applications provide a consistent response time, measured at the server TCP port in use, irrespective of the number of requests.
To achieve this the developer must avoid or remove all performance bottle-necks. Currently the most challenging issue is the scalability of distributed RDBMS systems.

Performance implications of using WF to control UI navigation in ASP.NET MVC application

I need to build a web application with different process flows and different UI steps depending on the locale of the logged in user.
I have developed a number of ASP.NET applications in C# and like the separation of concerns an MVC approach would give me. So I am looking at using these technologies.
The kicker is that different users in different locales need to have very different experiences, despite accessing the same datasource. I'm also constrained by the requirement to have new process flows be able to be configured easily. The XAML based Windows Workflow Foundation looks like a good candidate, and would allow me to avoid developing my own process flow engine.
However, I am a little concerned about the performance implications of such an approach. Has anyone tried this sort of architecture? What sort of impact can I expect on request time, CPU utilization and memory consumption?
All opinions gratefully received, Thanks.
Howdo
The principle objection, and I suppose, performance risk, which although not specically related to your ask, is that windows workflow hasn't been designed for that type of scenario. Simply put, WF first design tenet, was to enable long running transactions, built around web service and SOA, i.e. transactional connectivity lasting days, and as such its runtime is optimised for it. It doesn't really make a good fit, especially when you will need to shoe horn it into working, and it will be much more resource hungry for short running workflows, i.e. in relation to state changes, caching, etc, in terms of comparable other process flow code/engines. If you do go ahead, get a pilot up and running and test to death using Mercury Load Runner.
scope_creep

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