IIS 7 and Above
IIS Worker Process hangs every two hours
Last post Oct 16, 2019 03:12 PM by Lewis-H
Feb 20, 2017 06:10 PM|igmakis|LINK
As the subject says IIS Worker Process hangs every two hours (precisely) , and I'm not sure how to approach this problem.
Only thing that's for sure is that in every instance that problem occurs in the Performance Monitor's 'Analyze Wait Chain...'
lsass.exe is visible as a process which w3wp is waiting for to finish.
When lsass.exe finishes it's job, because of the piled up threads everything is unresponsive due to a 100% CPU usage and it
lasts for about 2 minutes.
As this is happening periodically in exactly two hours span I was convinced that some task on the particular system is causing the problem so I checked:
Any suggestion how to solve this problem will be much appreciated.
Feb 20, 2017 06:21 PM|HostingASPNet|LINK
When the IIS hangs check the Worker Processes in the IIS and check if there are requests that takes more time, i.e. hangs for some reasons.
Feb 20, 2017 07:08 PM|igmakis|LINK
Thank you kindly for your reply, but the problem is that the whole system becomes unresponsive and until
lsass.exe finishes it's impossible to refresh worker requests.
Forgot to mention that the whole mess started couple of days ago and before that no system or content changes have
been done at all. At this moment only one thing comes to mind... maybe cloud provider changed something on
a higher level environment.
Feb 20, 2017 09:59 PM|carehart|LINK
- No Application Pool recycling happened
I would have wondered about app pool recycling, but you say "none happened". Let's dig into that a bit before moving on. Because of course by default they should happen, for any of various reasons. So first are you saying that you enable all logging of recycle
events (most are not logged, by default, as controlled in each app pool's advanced settings), and still none EVER happen? Have you really turned off all recycling options?
Or did you mean to say that you see none logged "at the time of the hangup"? Well, do beware that the mechanism may not log when the recycle STARTS but when it FINISHES [edit: I had that order reversed by mistake when I first posted this reply], and as such
perhaps one app pool IS still recycling at the time of your observed hangup. Do things eventually clear? If so, then you'd think any hung recycles at least then SHOULD be logged, and you'd want to check the event logs then (perhaps well after the time of the
And I know you say (in reply to another person) that the whole server hangs up, but since you know when it's about to happen, I wonder if you were watching in the "Worker Processes" feature (at the server level), whether you would see a new app pool starting.
As you may know, when an app pool recycles, you will see there both the old one "stopping" and a new instance of it starting (two of the same name, I mean, though it may happen so fast that you never see it).
You could also be watching Windows Task Manager, sorting it by name, and watching the processes for how many w3wp.exe's you see, to see if the number increases at this moment. And while by default you can't connect a given w3wp.exe to a given app pool by
name, you may be able to distinguish them by the username (since each runs as itself/the app pool identity by default), or you can add the "cmd line" as a column in Task Manager to see what app pool a given w3wp.exe is representing.
If you would say again that things are so hosed at that moment that you can't even launch task manager, you may want to investigate tools that track processes over time (like NewRelic Infrastructure, formerly NewRelic Servers), to see what processes it shows
are running in the moments before and after the hangup (it may be able to write to those even if you can't get the UI to respond).
I appreciate that your main focus is the LSASS.exe process, and if that gets you to the solution great. But I offer all this in the meantime.
Hope something there may be of some help.
Feb 21, 2017 06:55 AM|igmakis|LINK
Hi, thank you for your thorough reply...
Regarding pool recycling, you're right, I've failed to give full/correct info. Pool is recycling regularly at predetermined time and it's logged as it should be. No problem there.
What I meant to say is that no recycling occurs during hang/wait time. Of course, I do monitor all available resources live, writing
down current worker process PID and checking it afterward when the whole mess stops. No change. Additionally i'm using PS to determine w3wp StartTime and the result is always expected, last scheduled recycle.
Thank you for the tools suggestion, i'll most certainly give it a shot.
Sep 26, 2019 03:46 PM|yudindm|LINK
I know that is an old question, but I got similar symptoms.
All clients browsers hang waiting response from IIS.
The only solution is to restart IIS.
Do you have solution to your problem?
Oct 16, 2019 03:12 PM|Lewis-H|LINK
This is how you can increase # of worker process