Iis – HTTP Error 503. The service is unavailable

asp.netiisiis-8

I'm struggling to setup the environment in IIS8, I searched a lot but couldn't find a right solution.

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I checked the error logs, but no idea.

C:\Windows\System32\LogFiles\HTTPERR

  1. 2013-10-09 09:28:39 192.168.43.205 60172 192.168.43.205 80 HTTP/1.1
    GET / 503 2 AppOffline qa.hti.local
  2. 2013-10-09 09:28:39 192.168.43.205 60192 192.168.43.205 80 HTTP/1.1
    GET /favicon.ico 503 2 AppOffline qa.hti.local

Then in Event Viewer:

WARNINGS:

  1. A listener channel for protocol 'http' in worker process '11188'
    serving application pool 'qa.hti.local' reported a listener channel
    failure. The data field contains the error number.
  2. A listener channel for protocol 'http' in worker process '7492'
    serving application pool 'qa.hti.local' reported a listener channel
    failure. The data field contains the error number.
  3. A listener channel for protocol 'http' in worker process '9088'
    serving application pool 'qa.hti.local' reported a listener channel
    failure. The data field contains the error number.
  4. A listener channel for protocol 'http' in worker process '9964'
    serving application pool 'qa.hti.local' reported a listener channel
    failure. The data field contains the error number.
  5. A listener channel for protocol 'http' in worker process '7716'
    serving application pool 'qa.hti.local' reported a listener channel
    failure. The data field contains the error number.

I don't understand what the warning means.

ERROR: Application pool 'qa.hti.local' is being automatically disabled due to a series of failures in the process(es) serving that
application pool.

Note: I learned that consecutive 5 failures leads to APP Pool crash, and this can increased. I also tried increasing this but no success.

OS: Windows server 2012
IIS Version: 8

Please share your thoughts.

Best Answer

FYI -

I'd like to add that I too am experiencing this, and have a vested interest in a solution. That said, my spec's seem to match yours, however I'd like to know about your server load.

OS: Windows Server 2012 Standard

IIS: IIS 8

Application Stack: .NET 4.0

The one thing we notice, is this problem does NOT happen when there isn't any load. We can hit the server all day with just 5 or 10 users, but the second the server comes into production with the others in the farm, we get intermittent and random 503 issues.

How many clients/users are connecting to your server?

Have you tried the following:

Application Pool Advanced Settings:

Queue Length: Default is 1000, try setting it to 5000 if you have an x64 system, and more than about 4GB of RAM

NOTE ON QUEUE LENGTH: On the Queue Length, you might actually see errors in the HTTP System Error logs that correspond with the App Pools dying. If you do, this might be a fix.

Private Bytes Memory: Are you specifying a setting here, or is your value "0" (Means unlimited).

let us know your findings, and if the Queue Length works for you.

Let us know on those

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