Good Reading on ASP.NET in Network-Load Balancing Environment - asp.net

What are some good web pages to read to become familiar with the ins and outs of creating asp.net web applications in an environment implementing Network-Load Balancing?

Try to use no Session State as this will have to be available on all WFE Servers, or configure it so it will use an out of process provider, like SQL
Take a look here:
http://msdn.microsoft.com/en-us/library/ms178581.aspx
and
http://msdn.microsoft.com/en-us/library/ms178581.aspx

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ASP.NET MemoryCache Sharing Across Applications

I have been reading all over the place about the new MemoryCache class starting in .Net Framework 4.0. From what I've read, you can access the MemoryCache across different .Net applications. I am trying to share an object between an Asp.Net application and a standard windows forms .Net application. If I add the object to the MemoryCache in the .Net application, the Asp.Net application does not see it. Is there any way to accomplish this? Thank you for your time, it is greatly appreciated.
Windows Form App:
Dim cache As ObjectCache = MemoryCache.Default
Dim policy As New CacheItemPolicy()
policy.AbsoluteExpiration = DateTimeOffset.Now.AddMinutes(60)
cache.Set("testcache", TestObj, policy)
Asp.Net App:
Dim cache As ObjectCache = MemoryCache.Default
If IsNothing(cache("testcache")) Then Response.Write("TestCache Is Nothing")
Thanks -
Ryan
No, that's not possible. MemoryCache is not a distributed caching solution. So it will only be available locally.
If you are looking for a distributed cache alternative you may want to look into AppFabric or Redis.
However, it does sound a bit like an odd architecture to want to share the cache that way.
Maybe exposing a shared services layer, that both the asp.net and winforms consume, and have just the services implement the caching would seem more logical (take into account I actually know nothing about the problem you are trying to solve, so I could be wrong).
Caching is more commonly used for performance reasons, not as a way to share data among applications.
MySQL memory tables are working great and having stellar performance. 20/30 inserts a second and only around 1% CPU load.
I realize this advice is not timely, but for others reading this question, another possibility is Interprocess Communication (IPC) between the two programs. This way the two programs can exchange messages/data directly without going thru an intermediate.
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365574(v=vs.85).aspx
From the documentation above, here are some of your options.
Clipboard
COM
Data Copy
DDE
File Mapping
Mailslots
Pipes
RPC
Windows Sockets
In your case, mapped memory files might be the best approach as it allows for a shared memory space between applications. Fundamentally, your MySql/Redis approach is probably not that different.
if you are interested in :
single server multiple applications - memory share
you should consider create web api at the same node and consume it (simple key value API)
and use simple Memory Cache provided by .net framework
multiple servers - memory share
free $$ solution
you can use "Distributed SQL Server Cache", allows the
distributed cache to use a SQL Server database as its backing store.
To create a SQL Server cached item table in a SQL Server instance,
you can use the sql-cache tool. The tool creates a table with the
name and schema that you specify.
if you have a cluster of nodes you can use NCache it is
an open source in-memory distributed cache developed natively in
.NET and .NET Core. NCache works both locally and configured as a
distributed cache cluster for an ASP.NET Core app running in Azure
or on other hosting platforms.
solutions that require paying money:
NCache mentioned previously, there's Professional and Enterprise solutions,
or
Redis Cache - Redis is an open-source in-memory data store, which is often used as a distributed cache. You can configure an Azure Redis Cache for an Azure-hosted ASP.NET Core app, and use an Azure Redis Cache for local development.

ASP.NET warmup/initialize

I'm trying to eliminate (or at least minimize) startup/warmup times for my .NET applications. I'm not really sure on how to do this even though it's a common concern.
There's a ton of questions about slow startup of .NET applications. These are easily explained by pool recycles, worker process startup, dynamic compilation of .aspx files, JIT etc. In addition, there are more things that may need to be initialized within the application such as EntityFramework and application caches.
I've found alot of different solutions such as:
ASP.NET Precompilation
IIS 8 Application Initialization (and for IIS 7.5)
Auto-Start ASP.NET Applications
However, I'm not entirely satisfied with any of the solutions above. Furthermore I'm deploying my applications to Azure Websites (in most cases) so I have limited access to the IIS.
I know that there are some custom "warmup scripts" that uses various methods for sending requests to the application (e.g. wget/curl). My idea is to create a "Warmup.aspx" page in each of my ASP.NET applications. Then I have a warmup service that sends an HTTP GET to the Warmup.aspx of each site every ... 5 minutes. This service could be a WorkerRole in Azure or a Windows Service in an on-premise installation. Warmup.aspx will will then do the following:
Send an HTTP GET to each .aspx-file within the application (to
dynamically compile the page)
This could be avoided by precompiling the .aspx pages using aspnet_compiler.exe
Send a query to the database to
initialize EntityFramework
Initialize application caches etc
So, my final question is whether there are better alternatives than my "Warmup.aspx" script? And is it a good approach or do you recommend some other method? I would really like some official method that would handle the above criteria.
Any and all suggestions are welcome, thanks!
Did you try this IIS Auto-Start feature described here ?
https://www.simple-talk.com/blogs/2013/03/05/speeding-up-your-application-with-the-iis-auto-start-feature/
You could have two instances of the site. When you need to deploy a new version, and therefore suffer a startup cycle, remove one instance out of load balancer rotation, deploy and start it, set it in and do the same for instance 2. A rolling deployment.

Recommended architecture - Server application that provides a ASP.NET Web front end

I'm having a look at the best way of developing a server application that presents an ASP.NET MVC front end for management/reporting.
The server app (service?) will also need to provide TCP listener as well as communicate to devices on a COM port.
The most obvious way I can think of doing this is to have an ASP.NET MVC web app and have a windows service that talks to the web app using a web calls/services. I guess then I'd talk to the service using the tcp listener or remoting?
The only other way would be to actually host an web server component in the service, and not use IIS which seems a bit to over the top.
Does anyone have any experience of this/recommendations?
It's a bit open ended but hope I've explained the basics.
TIA
Sam
I would probably try and decouple things a bit more.
Start off w/ a core project where all your business logic lies (agnostic of how users interact with it); sort of the DDD Domain Model idea.
Then, create two projects which consume that core project, one that is your MVC app, and another that's a WCF or ServiceStack-based service which can handle your TCP stuff.
Share state between them using the normal means; either inter-process comms, shared database, etc.
It sounds to me like you're looking for something very close to Windows Communication Foundation. Your requirements for IIS hosting, ASP.NET communication, and TCP communication. MSDN has a brief overview of WCF up here. There's also an article available about the transportation protocols here.
There are some good -- if a little old -- WCF questions here on Stack Overflow. I've just started delving into this world myself, and I have to admit that it's daunting at first. The Beginner's Guide (found under the first hyperlink above) has some slightly old, but very useful tutorial videos about WCF.
I will say that, although it may seem daunting or difficult, it's certainly better to use an existing, established technology for your purposes than to try to write your own homebrewed solution for something like this.
I started ServiceStack because I needed a high-performance web services framework option that promotes the correct way to develop web services.
ServiceStack can be run on top of any ASP.NET host or self-hosted using the HttpListener option. See the Starter Templates for example projects of a Console App or Windows Service hosts. Although even under IIS, ServiceStack is very fast and imposes very little overhead with a hello world service executing in sub <1ms response times.
ServiceStack also comes with .NET's fastest text serializers and a myriad of high-performance caching providers so you can escape the XML config bound ASP.NET's session and caching provider model.
Because ServiceStack encourages a clean message-based development model your same web services can take advantage of the Redis MQ Host allowing it to be invoked outside of HTTP context using Redis as a broker - with no code-changes required.
Redis is one of the fastest distributed NoSQL data stores.

Determine if asp.net application support load balancing environment

I am new to asp.net, I have been tasked to upgrade the physical architecture to load balancing environment to support the application.
I done some reading the session state should be configure to Out-Process instead of In-Proc to support load balancing.
Is there any other issues I need to take note for asp.net web application to run in the load balanced environment?
if you are going to have your session out of proc, your session objects should be serializable. If you want a quick solution, sticky sessions are an option. You can read about it here

Building my first ASP application

I've just been tasked with building a web application using ASP (.net) and am looking for some advice on where to start. In a nutshell the application needs to be able to.
Handle user verification / authentication
Handle sessions
Do SOAP messaging
The application is intended to act as a front end for system functions that are accessible via web service calls.
I intend to do a lot of work on the client side using JavaScript and am thinking of using ASP solely as the framework for the 3 items I listed above.
Appreciate any suggestions you may have.
Use Visual Studio 2008 if you can. Its support for Ajax client libraries and javascript intellisense is very good. (Check out the jQuery add in)
ASP.NET has built in Login controls (and the membership services mentioned by ChrisE), and also has Forms Authentication. Try to leverage these existing components and avoid using session to store user specific objects/data.
---session rant
Its sometimes unavoidable, but you should avoid it whenever you can. It incurs a burden on the webserver for each user, and that leads to some very difficult scaling problems. The FormsAuthentication Ticket has a value property that you can store about 4K worth of user data in - try to use that instead.
---End session rant
Try to use a MVC approach (not necessarily an ASP.NET MVC), but at least one that seperates your presentation / view layer from the data / model layer.
Create a default theme and use it. Most sites will need to have multiple themes later, and refactoring that will be a PIA.
If you need SOAP to interact with Non-.NET services then by all means use it. If you are only connecting to .NET services then look into WCF clients and services. They will give you more flexibility.
If you are doing the client work in javascript, then dont use the update panel. It adds lots of overhead.
Get FireFox + FireBug + YSlow, and IE8 (yeah its beta still). They will help you when dealing with the client end of debugging / styling.
Take a look at the rules for website performance, but take these with a grain of salt. They are intended for very large sites, and some of the items may not be applicable (CDN, DNS lookups, Redirects).
WCF for Soap -- I would also suggest picking this up:
alt ASP.NET 3.5 http://ecx.images-amazon.com/images/I/518N8vYWf1L._SL500_AA240_.jpg
This book is in tutorial form -- and Jesse Liberty is a great teacher (as are his co-authors).
ASP.NET provides out of the box authentication/authorization through the SqlMembershipProvider and SqlRoleProvider classes, or you can use the ADMembershipProvider along with a custom RoleProvider to authenticate and authorize against an Active Directory setup.
Session handling is readily provided by ASP.NET as well, through an in-process server, an external StateServer service, or through a connection to SQL Server (and of course, you can provide a custom Session service if you need something different).
As Lou Franco mentioned, WCF provides the framework for the SOAP calls, and will blend in with your ASP.NET application quite handily.
If you are using ASP.NET Web Forms then for handling user authentication/verification I'd recommend ASP.NET Membership services http://msdn.microsoft.com/en-us/library/yh26yfzy.aspx because it does some of the heavy lifting for you and also helps you from making any elementary security mistakes.
This is not directly related to your requirements, but I'd suggest you study the differences between Web Site and Web Application. The sooner the better. Everything will go smoother if you understand how the project is managed.
You can start here: http://www.codersbarn.com/post/2008/06/ASPNET-Web-Site-versus-Web-Application-Project.aspx

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