I am trying to diagnose a problem with app pools crashing in an ASP.NET application.
My environment:
· Windows Server 2003 Enterprise x64 Edition, Service Pack 2
· .NET 3.5
· Windows Debugging Tools (64-bit)
In terms of symptoms, I am seeing entries in the Windows Application Event Log such as:
Faulting application w3wp.exe, version 6.0.3790.3959, stamp 45d691cc, faulting module kernel32.dll, version 5.2.3790.4062, stamp 462643a7, debug? 0, fault address 0x0000000000027d8d.
These are accompanied by entries in the httperr log such as:
80 HTTP/1.1 GET /Default.aspx - 1775306986 Connection_Abandoned_By_AppPool [poolname]
Additional information about the crashes:
· They do not seem to happen at any particular time of day. Sometimes there are no crashes for a few days, other times there is some activity every 12 hours or so, other times there are multiple crashes every 30 minutes or so over a period of several hours.
· As the crashes also happen during the “off hours” for the application, load is not necessarily an issue. The web servers are also generally under a relatively low utilization levels.
· Occasionally there will be one or two crashes a few minutes apart, but more often than not there are there 3+ crashes in quick succession. With the default app pool rapid-fail protection configuration in place, the app pool is disabled when more than 5 crashes occur within a 5 minute span of time.
· There are a number of servers in a hardware load-balanced setup. Not always, but usually multiple servers are affected at about the same time.
· Httperr log entires show the “Connection_Abandoned_By_AppPool” messages for various requests – .asmx, .aspx and .svc (WCF).
I have attempted to capture a dump file using ADPlus, without any success. I attached the debugger using the following command:
Adplus.vbs – c c:\ad.config –pn w3wp.exe
The config file passed in is as follows:
<ADPlus>
<Settings>
<RunMode>crash</RunMode>
</Settings>
<Exceptions>
<Config>
<Code> AllExceptions </Code>
<Actions1> Void </Actions1>
<Actions2>MiniDump;Log;Time;</Actions2>
</Config>
</Exceptions>
</ADPlus>
The debugger starts up successfully and I see the following in the log:
0:052> *
0:052> * ADPlus is monitoring: W3WP.EXE_[app pool name]
0:052> * for 1st chance and 2nd chance exceptions as configured above.
0:052> * To change ADPlus configuration please refer to ADPlus.Doc. This file can be found
0:052> * in the same folder as ADPlus.vbs
0:052> *
0:052> g
However, when the app pool crashes, there is no dump created and no entries in the log, other than something like:
Executing custom commands
User Mode Time
Thread Time
30:a98 0 days 0:00:00.171
I believe the adplus configuration is correct. I have verified this by attaching it to a sample console application set up to simulate a crash due to a null pointer exception and attaching it to w3wp.exe and simulating a crash due to a null pointer exception in a timer. However, when that happens, the event log entries automatically generated already contain a stack dump and all the necessary information for me to debug the issue. These crashes unfortunately do not provide any information other than what is mentioned above.
So at this point my question is twofold:
1. Why am I unable to obtain a crash dump of w3wp.exe using adplus?
2. What else can I try to diagnose w3wp.exe faulting?
Any assistance would be much appreciated.