Is there a way to recycle and afterwards reload an application pool?
My problem has been slow performance when logging in to my web application. I found out that the "Idle Time-out(minutes)" was sat to 20 by default. This caused the application to terminate when idle so that it can start up again on the next visit. After searching the web i found out that this value could be sat to 0 so it won't terminate. However, the first visit after recycling, an app pool have to create a new w3wp.exe worker process which is slow because the app pool needs to be created, ASP.NET or another framework needs to be loaded, and then the application needs to be loaded. Source right here
This means that every time the app recycles, the first visitor have to wait longer then the other visitors when logging in, doing some stuff and log out.
The web application is using the ISS from Dynamics AX 2009.
Sorry I thought you are working on IIS 7.5
But there was a beta for this in IIS7 actually.
I think you are looking something along the lines of this
A warmup module for IIS 7.5
"IIS Application Initialization for IIS 7.5 enables website administrators to improve the responsiveness of their Web sites by loading the Web applications before the first request arrives. By proactively loading and initializing all the dependencies such as database connections, compilation of ASP.NET code, and loading of modules, IT Professionals can ensure their Web sites are responsive at all times even if their Web sites use a custom request pipeline or if the Application Pool is recycled. While an application is being initialized, IIS can also be configured to return an alternate response such as static content as a placeholder or "splash page" until an application has completed its initialization tasks."
Download Link
http://www.iis.net/downloads/microsoft/application-initialization
And also have a look at this; which basically talks about using warm up classes which comes with ASPNET 4
http://weblogs.asp.net/gunnarpeipman/archive/2010/01/31/asp-net-4-0-how-to-use-application-warm-up-class.aspx
Checkout the suspend option.
IIS now has
Idle Time-out Action : Suspend setting
Suspending is just freezes the process and it is much more efficient than the destroying the process. Because it uses the same process and does not create another one after waking up.
Related
Ok so I understand how app pools work and what they do but I am wondering what exactly the app pool is, I am thinking at the moment that it is just information the metabase or some config file for use with http.sys?
I suppose another questions is, who or what spawns the worker process when a request is made?
thanks
The confused
First you can see the application pool as the program that actually is one with your pages and runs them. So what ever you make programmatically on your pages are done using the application pool.
For example:
user request the page a.aspx
IIS see that is asp.net page and assign it to one app pool
application pool see the a.aspx, check if is complied, and runs it - run your code.
Second you can see the big view, that there are many web sites lives together on one server and application pool is handle one or more web sites together.
Now, a web application can be run on one application pool, or on many application pools at the same time on the same server (this is called web garden). An in each of that you can run many threads.
Now for more details you can read the official microsoft pages.
We are using IIS7 to host an asp.net web-based application.
In this environment administrators and developers can deploy code to the application on a regular basis.
The new code or app goes as a DLL to the ASP.NET bin folder. Upon deployment of the new DLL, IIS restarts the process, impacting (slowing down) all online users.
Is there a way to configure IIS to run the process in the background and once ready make the switch from old state into new without impacting the users?!
Thanks in advance for your feedback!
IIS already does this, that's what recycling is all about. IT's loading the DLL's while the old version of the application is still running. only after this is completed the recycling is complete.
However loading the DLL's is only part of getting web applications ready, there might also be initial loads like loading/caching the user db etc.
These actions are not part of the recycle process, they happen after all DLL's reloaded and the recycling is already completed.
A while back I ran into this issue with an application that had a huge startup time due to heavy db activity/caching during startup. So I was interested if there is some functionality that allows us to execute code before the recycle is marked as completed, so that the application is first considered recycled when everything is ready to run. Basically what I wanted is some kind of staging functionality.
I was in contact with the IIS team regarding this issue, sadly they told me that no such functionality exists, nor is it planned.
To solve this you could try do the following:
Use alternating deploys:
You setup 2 Websites with separate application pools. One of them is the LIVE website the other one is the STAGED website. If you want to deploy changed you simply deploy to the STAGED website. After everything is loaded/cached etc. you switch the URL settings of the web applications to reroute incoming requests from the LIVE to the STAGED one. So the LIVE one becomes the new STAGED and the other way around. The next deploy would then go to the new STAGED again and so on.
UPDATE
Apparently they have created a IIS Module that provides this functionality by now:
IIS Application Warm-Up Module for IIS 7.5
The IIS team has released the first beta test version of the
Application Warm-Up Module for IIS 7.5. This makes warming up your
applications even easier than previously described. Instead of writing
custom code, you specify the URLs of resources to execute before the
Web application accepts requests from the network. This warm-up occurs
during startup of the IIS service (if you configured the IIS
application pool as AlwaysRunning) and when an IIS worker process
recycles. During recycle, the old IIS worker process continues to
execute requests until the newly spawned worker process is fully
warmed up, so that applications experience no interruptions or other
issues due to unprimed caches. Note that this module works with any
version of ASP.NET, starting with version 2.0.
For more information, see Application Warm-Up on the IIS.net Web site.
For a walkthrough that illustrates how to use the warm-up feature, see
Getting Started with the IIS 7.5 Application Warm-Up Module on the
IIS.net Web site.
See:
http://www.asp.net/whitepapers/aspnet4
If you use ASP.NET 4 Auto Start feature:
You can still choose to auto-recycle the worker processes from time to
time. When you do that, though, the app will immediately restart and
your warm up code will execute (unlike today - where you have to wait
for the next request to-do that).
The main difference between Warm Up and Auto Start feature is that the Warm Up Module is part of the recycling process. Rather than blocking the application for requests, while running the init code.
Only thing you get by using the Auto Start feature is that you don't have to wait for a user to hit the page, which does not help your case.
See the Gu's blog post:
http://weblogs.asp.net/scottgu/archive/2009/09/15/auto-start-asp-net-applications-vs-2010-and-net-4-0-series.aspx
UPDATE 2:
Sadly the Warmup Module has been discontinued for IIS 7/7.5:
http://forums.iis.net/t/1176740.aspx
It will be part of IIS8 though (It's now called Application Initialization Module):
http://weblogs.asp.net/owscott/archive/2012/03/01/what-s-new-in-iis-8.aspx
UPDATE 3:
As pointed out in the comments the Warmup Module resurfaced for IIS 7.5 as Application Initialization Module for IIS 7.5 after IIS 8 was released:
http://www.iis.net/downloads/microsoft/application-initialization
The first part of ntziolis answer is a wee bit inaccurate. The worker process isn't being recycled or restarted, it just keeps running. If this were the case, then in shared pool environments you would have sites knocked out every time a new one was deployed.
When you deploy a new ASP.NET application it's the site's "Application Domain" within the worker process is torn down, not the pool process.
In addition pool recycling is a completely separate concept to deployment
At this point in time in the commercial life of ASP.NET, during a deployment, a site will be in an inconsistent state until all of the site is deployed. There is still no good story about this from Microsoft at this time for single site on a single server deployments.
This is why ASP.NET has the special App_Offline.htm page. It's there so you can enable that page, deploy and then turn it off.
The second part of ntziolis answer is nearly correct but you don't need two sites or two application pools. You just need two file system folders that switch between being the physical folders for the site...if you're on a single server and not behind a load balancer or ARR.
If your sites were on a web server behind a load-balancer or ARR then having two different sites would make sense, you could route requests from one site to the other and round-robin on each deploy.
Obviously if there is a large amount of user generated content (uploaded files and the like) then you'd map a virtual directory in your site to a common location for this data.
In larger scale deployments where your app is running across (for example) a load-balanced environment you can do more sophisticated deployments.
For related questions please see:
How Do I deploy an application to IIS while that web application is running
Publishing/uploading new DLL to IIS: website goes down whilst uploading
Is smooth deployment possible with componentized ASP.NET MVC apps?
We would like to warm up an ASP.NET MVC application hosted on IIS 7.5 server. The warm up module that used to be available at http://forums.iis.net/t/1176740.aspx has been removed since sometime.
The application should be warmed up everytime IIS or ASP.NET worker-process restarts for any reason. During the warm up period, IIS should return some HTTP status code signifying its warm up state or its inability to serve any clients.
Would creating a executable that navigates through necessary pages in the site via HttpRequests be a good idea? The executable can be triggered from IProcessHostPreloadClient implementation. Is it possible to configure IIS so that it would only accept requests from localhost and once the executable is done, it can switch over to all clients - but that switch should not trigger an IIS restart (obviously).
Is it possible to use an Visual Studio 2010 - Web Performance Test to warm-up an application instead of creating an manual executable? Any other alternatives?
PS: The application uses Forms Authentication and uses sessions - so maintaining state cookie and other cookies is important.
UPDATE 1 - We are using .NET Framework 4.0 and Entity Framework (database first) in our application. The first time hits to EF queries are slow. The reason behind the warm up is to get these first time hits out of the way. We are already using compiled queries at most places and we have implemented pre-compiled views for EF. The size of the model and application is very large and complex. Warm up needs to walk through many pages to ensure that compiled and non-compiled EF queries get executed at-least once before any end user gets access to the application.
Microsoft has released a module that does exactly what you ask for. The Application Initialization Module for IIS 7.5 improves the responsiveness of Web sites by loading the Web applications before the first request arrives.
You can specify a series of Urls that IIS will preload before accepting requests from real users. I don't think you can get a true user login expereince, but maybe you can set up simulated pages that does not require login that fulfills the same warmup you ask for?
The feature I think is most compelling is that this module also enables overlapped process recycling. The following tutorial from IIS 8.0 include a step-by-step approach on how to enable overlapped process recycling.
When IIS detects that an active worker process is being recycled, IIS does not switch active traffic over to the new recycled worker process until the new worker process finishes running all application initialization Urls in the new process. This ensures that customers browsing your website don't see application initialization pages once an application is live and running.
This IIS Application Initialization module is built into IIS 8.0, but is available for download for IIS 7.5.
You may take a look at the following post for the Auto-Start feature built into IIS 7.5 and ASP.NET 4.0.
Any application that generates a server request for the hosted resources can be used to warm up an IIS process. Exactly how many requests you need depends on what parts need warming up. Typically, warm-up is used for:
Starting up a worker process. For this, you only need to ask for one resource to warm up a process for the entire application.
Perform any static initialization, database startup, or pre-caching. Anything you do in your Global.asax file will happen when you do your first request, so if you can make all of your initialization happen then, you'll still only need to make one page request.
Force pre-compilation of ASP.NET pages. For this to happen you would need to hit every page. Fortunately, this is typically not much of a time cost, so you likely don't need to worry about it. If you do have individual pages that load slowly, you can warm them up separately.
The "warm-up" process here isn't anything magical. You just need force IIS to serve the URL in question. Everything you mentioned would take care of that: using a stress-test tool to query the URL, writing a custom utility to post HTTP requests, even just scripting out a tool like 'wget' or a PowerShell script to download the URLs would do it.
As far as restricting access to localhost, as far as I know, within IIS, the only way to change that requires you to restart IIS. You could always build a pre-request hook into your application and maintain the state there, and have your warm-up process query some specific URL that toggles that state to "open". But I'm not sure what you would accomplish. If, somehow, a user did try to query your site before your warm-up finished, all that would happen is your site would take a long time to respond, then they would eventually get the page they asked for. If you locked them out of the site during warm-up, they would instead get a browser network error that claimed the site was offline, which (to me) sounds much worse.
I've got an application that needs to do some work on startup (before the first request is in).
I've added the initialization code in the global.asax file (Application_start method) but this code doesn't seem to be hit after an iis reset is performed.
Is there an event which is triggered in an asp.net application when an iis reset has occurred?
Thanks.
Application start happens on first request, not on iisreset.
The site doesn't start itself..
See "Restart cache item callback on web process restart" here.
In such cases, the service will stop
running unless a page is hit and the
Application_Start is called.
Application_Start is called only when
a page is visited for the first time
in a web project.
I would suggest having a batch file that contains iisreset and an "iexplore mypage" call
Edit: apparently, you can use application end to trigger application start. YMMV
http://weblogs.asp.net/scottgu/archive/2009/09/15/auto-start-asp-net-applications-vs-2010-and-net-4-0-series.aspx
This may be of help to you.
Tho the features are new to IIS 7.5 which is only on Windows Server 2008 R2 / Windows 7.
Auto-Start Web Applications with ASP.NET 4
Some web applications need to load large amounts of data, or perform expensive initialization processing, before they are ready to process requests. Developers using ASP.NET today often do this work using the “Application_Start” event handler within the Global.asax file of an application (which fires the first time a request executes). They then either devise custom scripts to send fake requests to the application to periodically “wake it up” and execute this code before a customer hits it, or simply cause the unfortunate first customer that accesses the application to wait while this logic finishes before processing the request (which can lead to a long delay for them).
ASP.NET 4 ships with a new feature called “auto-start” that better addresses this scenario, and is available when ASP.NET 4 runs on IIS 7.5 (which ships with Windows 7 and Windows Server 2008 R2). The auto-start feature provides a controlled approach for starting up an application worker process, initializing an ASP.NET application, and then accepting HTTP requests.
Edit: Link to more information about Auto Start feature.
http://www.asp.net/LEARN/whitepapers/aspnet4#0.2__Toc253429241
Scenario: I've an n-Tier enterprise ASP.NET application deployed using Web Deployment Projects. All tiers produce independent assemblies that is consumed by the ASP.NET application.
Problem: When I run the app. for the first time after deployment it takes lot of time to load dependent assemblies in memory. But once loaded its lighting fast app. In case if there are no users accessing the app, IIS unloads the assemblies from the memory and when a user tried to access the app on a later instance it goes on loading all the assemblies once again taking the same amount of time to load as it takes to do so for the first time.
I'm looking for a solution that enables me to keep my assemblies loaded into memory persistently overriding the volatile nature of assemblies towards memory residency.
Or any other solution that lets my users happily use the app resolving the mentioned problem.
In IIS 6, go to the Application Pools section, and right-click > Properties on the pool which hosts the ASP.NET application in question. Go to the Performance tab and uncheck "Shutdown worker processes after being idle for:"
In IIS 7, go to the Connections pane and find Application Pools, and select Advanced Settings for the pool which hosts your application. Find the "Idle Timeout" property and set it to "0" (this disables it).
The default is 20 minutes of inactivity. By unchecking the box, once your AppDomain is loaded by the worker process, it will never die (unless you kill the process or something of course). By default, IIS will recycle the process when it reaches some limit, such as a memory cap, but it will also start a new one and "phase over" all incoming requests until the old one is unused, so as to minimize disruption.
I've also written a small c# class which will keep your ASP.NET application alive (alternate archived version) under normal circumstances. Since it runs within the application, obviously it can't stop IIS or anything else from explicitly killing the process, but it will keep the application "hot", e.g. the app will never go idle long enough for IIS to decide to shut it off.
If you do not have direct control over your IIS configuration (shared host, for example) your best bet is to have a small application running on a separate system - say, an always-on workstation - which hits your site every x minutes to keep the application pool from timing out. Nothing fancy - a simple WebRequest and a while() loop in a console application will do.
One of the advantages of ASP .net is the posibility to create static (shared) instances of objects.
To avoid the necessity of an external process you can create an static timer in (per example) global.asax which calls for a page on the domain with a simple WebRequest. On this way the site keeps alive himself until a manual reset of the pool is done.
I wrote a little C# console application that keeps my 4 sites alive every 10 mins via windows task scheduler. Life is once again good. We do not run the app from 2-5am just so the serves can do any cleanups of memory, if it even matters. for our sites there is rarely anyone on at those hours anyway.