As far as I know the IDLE timeout will only be effective when startMode=OnDemand, however I found the following message in event log:
A worker process with process id of '2556' serving application pool 'xxxx' was shutdown due to inactivity. Application Pool timeout configuration was set to 20 minutes. A new worker process will be started when needed.
I've set the timeout to 5 minutes to help me found out the target setting, it seems the IDLE timer is still effective while startMode=AlwaysRunning.
I also found that a new worker process of that application pool is immediately started, however I was expecting that the application pool will not recycle every 5 minutes. Anyone know whats happening?
Related
I have an ASP.NET Core app — a RESTful API with websocket functionality through SignalR.
We have an issue when the application pool is recycled automatically every 29 hours - sometimes (rarely) it doesn't recover. Even manually, I can't restart the application pool.
Yesterday the only thing that helped was restarting the w3 publishing service.
By looking through logs I can see one moment the server responds nicely and fast with code 200 responses, then next it's all code 400 responses (?) and shortly thereafter 503.
Any idea what could be preventing it from recycling. The event log states in order:
A worker process with process id of '29752' serving application pool 'DefaultAppPool' has requested a recycle because the worker process reached its allowed processing time limit.
A worker process '29752' serving application pool 'DefaultAppPool' failed to stop a listener channel for protocol 'http' in the allotted time. The data field contains the error number.
Binary data:
In Words
0000: 800705B4
A process serving application pool 'DefaultAppPool' exceeded time limits during shut down. The process id was '29752'.
I have process named agent.exe, my app pool runs 2 instances of this process.
When recycle my AppPool then most of the times it works and those 2 instances are shutting down and 2 new instances are up.
but sometimes when I recycle my 2 old instances aren't shutting down while my 2 new instances are up and working, so I can have 4,6 and even more instances running.
Can I see why the instances aren't been recycled? I only found this http://technet.microsoft.com/en-us/library/cc735206(v=ws.10).aspx, but those are only informative logs and I can't see errors in them.
Does anyone know way to see recycling errors logs?
My server is Windows 2003 and I'm running IIS6.
It should be noted that there is no connection to "Overlapping recycling" because the instances don't shutting down at all.
thanks.
I found the following logs that can use to identify App Pool recycle errors:
AppPoolRecycleTime - Logs event on time-based recycles.
AppPoolRecycleRequests - Logs event on number of request-based
recycles. AppPoolRecycleSchedule - Logs event on schedule-based
recycless. AppPoolRecycleMemory - Logs event on memory-based
recycle. AppPoolRecycleIsapiUnhealthy - Logs event when worker
processes request recycles because an ISAPI reported unhealthy.
AppPoolRecycleOnDemand - Logs event when an administrator requests a
recycle of all processes in the application pool.
AppPoolRecycleConfigChange - Logs an event if an application pool is
recycled because one of the application pool properties that requires
a recycle to take effect has changed. AppPoolRecyclePrivateMemory -
Logs an event if an application pool is recycled based on private
memory.
taken from here:
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/87892589-4eda-4003-b4ac-3879eac4bf48.mspx?mfr=true
I have some questions about IIS application pool configuration.
I know that idleTimeout specifies how long a worker process should run idle if no new requests are received and the worker process is not processing requests. After the allocated time passes, the worker process should request that it be shut down by the WWW service (taken from here). My question is when and how the worker process starts when a request arrives after it shut down?
Other question is what is the difference between application pool recycling and between shut down? Does it better to recycke instead of shut down and then start again?
When and How worker process starts? When a new request comes in IIS spins a new process for the app pool your website is running under.
The difference between shutting down and recycle is that during a recycle a new process is started for the app pool in parallel, while the existing process is still serving an existing request. Any new requests that come in are handled by the new process. So in effect you do not loose any request that come in and any existing requests are not prematurely dropped. In a shutdown, you will loose the requests while the app is down.
To see this live in action - open task manager, select processes tab and see IIS spin up the app pool processes and notice the behavior between a shutdown and recycle. During a recycle for a brief moment you will see two processes for the same app pool.
See this video for a better understanding : http://dotnetslackers.com/articles/iis/IIS-Overlapping-App-Pools-Week-16.aspx
according to the the IIS documentation the rapid fail protection once activated leads to the deactivation of an application pool if a "failure" occurs. However, I could not find the definition of the "failure" case. In my web application I have a special exception that I would like the IIS to consider it as a "failure".
Does anyone have an idea? Thanks
This appears to have a list, for Server 2003 at least: http://web.archive.org/web/20130511004652/http://technet.microsoft.com/en-us/library/cc787273(WS.10).aspx
The WWW service shuts down an application pool whenever a worker
process in the application pool fails often enough to equal or exceed
the Rapid-Fail Protection (RFP) interval time window (for example:
five failures in five minutes). The WWW service detects failure
whenever:
A worker process does not start within the startup time limit.
A worker process does not shut down within the shutdown time limit.
A worker process shuts itself down because of a fatal error and sends
the WWW service an error code.
A worker process fails to respond to a ping message.
The WWW service detects that a worker process is sending non-standard
communications (the worker process may have been taken over).
(updated with archive.org to fix broken link, and replicated detail here)
The documentation for configuring rapid fail protection alludes to a "failure" meaning a worker process crash.
Through experimentation I've noticed that you should expect something like the following in Windows Event Application Logs for a w3wp.exe crash:
An unhandled exception occurred and the process was terminated.
Application ID: /LM/W3SVC/1/ROOT
Process ID: 2628
Exception: System.SomeUnhandledException
Indeed with rapid fail protection enabled with the default configuration, 5 such events within 5 minutes of each other cause the application pool to stop, and you'll see a further Windows Event Application Log similar to:
Application pool 'my-test-application-pool' is being automatically
disabled due to a series of failures in the process(es) serving that
application pool.
Is Recycling an App Pool programatically the same as starting and stopping the app pool in IIS.
Kind of, the difference being that during a recycle http.sys keeps the client connection alive whilst the worker process recycles and transparently routes new requests to the new worker process once it's started.
Also IIS (6 and 7) defaults to using "Overlapped Recycling". What this means is that IIS will start a new worker process before it shuts down the old worker process. Once the new process is started all new requests are directed to the new process.
If you stop and start the application pool you will dump all of your client connections and users may receive a Service Unavailable message whilst the new pool is being started.
Additional differences are:
You can do recycle to your application pool only, while stop & start influences all application pools.
When you are asking to recycle you have time to finalize your work (like saving your data etc.), which is not in restart.
You can schedule the IIS to run the recycle job depends on specific time, after period of time, depends on your memory consumption etc..