Apppool recycle side effects - iis

when we recycle app pool , will it crashes my website.
we have a basic public website. does recyclying the apppool every week causes the site to crash or it just kills the session of the users
we have system of out memory issue at the moment , until the we are recycling the app pool

If you keep your sessions InProc (default) then yes, recycling the application will kick out any logged in user, they will lose their sessions.
Out of Memory could be caused by many things. See How to Troubleshoot Out of Memory Issues (System.OutOfMemoryException) in ASP.NET

Related

IIS 8 Application pool recycle vs SignalR 2.3.0

I have a website in IIS 8.5.9600.16384, we communicate with thousands of mobile devices through cyclic synchronisation and through SignalR 2.3.0.
This morning we had an application pool reset during working hours, which caused the SignalR to call "OnReconnect" of all our mobile devices at the same time.
I though that IIS started new processes first and then killed the old, not having downtime.
Can somebody tell me exactly what happens when IIS recycles it's application pool on the SignalR side? And in which cases can there be a connection downtime? (ex : if the server is busy?)
Edited : The application pool was recycled by IIS because of the "time limit". The IT team will change this setting so that the application pools reset every day at night time when it will have a lower impact on our applications.
A worker process with process id of '8720' serving application pool 'DefaultAppPool' has requested a recycle because the worker process reached its allowed processing time limit.
Also confirmed that disallowOverlappingRotation is not set to True. Any hint would help.
A few years later, I'm still getting some problems with the application pool recycle and SignalR. We are occasionally seeing thousands of re-connections of SignalR while the application pool recycle occurs, opening more than 60k TCPIP ports and causing a crash in IIS.
We managed to have it run "okay" for quite some time but it still crashes. Any hint would help. thanks
I'd first identify how IIS was reset. If you experienced a crash or performed an IISReset, the processes would be down before a new one stood back up. If on the other hand you configured AppPool recycling, then the overlapping processes should occur as you mention. I would check the System Event Log for recycling messages. Note that not all recycle reasons are logged by default.
You may also check to make sure disallowOverlappingRotation is not set to True.
Specifies whether the WWW Service should start another worker process to replace the existing worker process while that process is shutting down. The value of this property should be set to true if the worker process loads any application code that does not support multiple worker processes.
https://learn.microsoft.com/en-us/iis/configuration/system.applicationhost/applicationpools/add/recycling/

Life MVC applications - IIS

I've a web application (MVC) that performs processes in different time intervals.
However, after a period of inactivity, the application "dies".
I guess that "kills" IIS.
What should I do that applications live permanently?
Is it possible that kills something else?
Each web application is executed by an app pool. App pools have an idle time, when that time is reached, the app pool shoots down until there is another request. You could set the idle time to a higher value.
https://technet.microsoft.com/en-us/library/cc771956
That say, it's a bad practice to have long running process in Asp.Net application. You should create a Windows Service for that.

How to prevent IIS from shutting down Web Site when not in use?

I have a web application hosted under IIS. It is a data warehouse, and during its startup process it requires instantiating a large set of items in memory (takes roughly ~20 minutes to fully set up). Because this website is critical to our company, this system must be online 100% during the daytime, and only can be restarted during off-work hours.
For some reason, this web application seems to be "offline" when there is no usage for some time. I know this because the cache is not fully instantiated when the website is visited. This is unacceptable.
It is not clear to me why the website is shut off. The application pool is only set to recycle daily at 4:00 AM (it is 11 AM now).
Are there other settings which I'm not aware of on the IIS part that causes it to shut down the website automatically?
Addl Note: The website does not shut off automatically when running in IISExpress in Visual Studio. Only the production version hosted on IIS shuts off.
Here's a screen of the Advanced Settings for the Application Pool the web site is running under. (Not sure if it's useful.)
I'm on IIS 7.5, Server 2008 R2. It is an ASP.NET 5 Web App.
Check Idle Time-out settings under process model in screenshot. That setting is causing app pool shutting down when remain idle for 20 mins. You can set it to 0 to keep it running all time even when its idle i.e. not processing any requests.
Note: Keeping app pool running all time will consume server's precious memory. It may become critical especially if application is leaking memory.

Does IIS Garbage Collect hosted Service applications when idle?

All,
I have developed a WCF ODATA Services application and hosted it in IIS7. The service application has an in-memory cache which loses all its cached value if the client is idle for about 15 mins or so.
While troubleshooting, i figured out that the application logic is proper and doesn't do a bulk removal of objects from the cache.
So, I am puzzled if IIS does clears the service objects when there are no client connected to it for quite sometime.?
Is this GC behavior true? If so, how do i control it?
Any help is much appreciated.
Thanks
By default the IIS7 Application Pools have a 20 minute Idle Timeout value set after which the application pool is unloaded from memory along with all your cached data.
You can increase the Idle Timeout or even set it to '0' which causes it to never timeout by selecting the application pool hosting your site in IIS Manager, choosing 'Advanced Properties' in the Actions pane and then setting the value of 'Idle Time-out (minutes) value' to the new timeout you want and clicking ok. (There are a couple of screen shots of this on Brad Kinsley's blog posting 'IIS7 Application Pool Idle Time-out Settings'
One option to consider is setting up an out-of-proc cache so that even if IIS does recycle your app, the memory cache persists or setup a backing store for your existing cache so that if the app pool recycles the cache re-populates from the backing store.
The Enterprise Library's Caching Application block is one example of a caching solution with such a backing store. See 'Caching Application Block and database backing store' for more information on that.

Stop IIS 7.5 Application Pool Recycling

How do stop application pools from recycling in IIS 7.5?
I have configured the following settings:
ProcessModel -> Idle Time-out (minutes) = 0
Recycling -> Regular Time Intervals (minutes) = 0
Are these settings enought to stop an application pool from recycling?
Yes, that should be ok assuming you also use Private Memory Limit = 0.
There are still reasons an AppPool could recycle, such as when adding a new Global Module, it will require to be recycled so configuration changes take effect, but you can also disable that using the "Disable Recycling on Configuratoin Changes".
Finally if you are running ASP.NET you should consider that still AppDomains will recycle when changes in config (such as web.config) happen. But that should not affect the AppPool per'se only the ASP.NET applications running in it (such as Session State), but again it depends on why you ask this question if this is important or not.

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