Exchange 2007 Backpressure

ddotson
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Hello-

Quick question.  One of our Exchange servers went into backpressure last night due to low drive space.  We resolved the issue, but there is no event in the event log indicating that backpressure has returned to normal.  We aren't getting reports of problems from endusers.

Is there a query that I can use in Powershell to tell me if it is still in backpressure?

Thanks,

Dan
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You will only get an event when diskspace is lower than threshold. If its under a normal range you won't get an effect

Regards,
v-2nas

Author

Commented:
We always get an event indicating that backpressure is decreasing.  We have not gotten that event in this case.  So how do we know if it is actually in backpressure or not?
Check the event viewer for following events, use filter option and specify the event based on your version. If you haven't played with the limits then default would be in effect. you can cross check the free diskspace whether its above or below the bp.

http://technet.microsoft.com/en-us/library/bb201658(EXCHG.80).aspx
  Back Pressure Logging Information in Exchange 2007 RTM
The following list describes the event log entries that are generated by specific back pressure events in Exchange 2007 RTM:

Event log entry for changes in resource utilization level
Event Type: Warning
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15001
Description: The resource pressure changed from Previous Utilization Level to Current Utilization Level.

Event log entry for constantly high resource utilization levels
Event Type: Warning
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15002
Description: The resource pressure is constant at High.

Event log entry for changes in memory utilization level by the EdgeTransport.exe process
Event Type: Warning
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15003
Description: Private bytes consumption changed from Previous Utilization Level to Current Utilization Level.

  Back Pressure Logging Information in Exchange 2007 SP1
The following list describes the event log entries that are generated by specific back pressure events in Exchange 2007 SP1:

Event log entry for an increase in any resource utilization level
Event Type: Error
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15004
Description: Resource pressure increased from Previous Utilization Level to Current Utilization Level.

Event log entry for a decrease in any resource utilization level
Event Type: Information
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15005
Description: Resource pressure decreased from Previous Utilization Level to Current Utilization Level.

Event log entry for critically low available disk space
Event Type: Error
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15006
Description: The Microsoft Exchange Transport service is rejecting messages because available disk space is below the configured threshold. Administrative action may be required to free disk space for the service to continue operations.

Event log entry for critically low available memory
Event Type: Error
Event Source: MSExchangeTransport
Event Category: Resource Manager
Event ID: 15007
Description: The Microsoft Exchange Transport service is rejecting message submissions because the service continues to consume more memory than the configured threshold. This may require that this service be restarted to continue normal operation.

Commented:

The problem is to write something generic for backpressure is really hard since backpressure depend on your specific hardware/configuration and load on your server.

Some values can be very high on your server and make it go into backpressure but could be normal values for other servers. So you see that it is no fixed values that triggers backpressure.

I suggest that that you use performance monitor and do benchmarking for your servers, then you can watch some counters and trigger alerts if they go above your threshold values.

You can also monitor applicationlog for backpressure events.

here are some articles that explain and give suggestions what you should watch for.

http://msexchangeteam.com/archive/2008/05/16/448901.aspx
http://msexchangeteam.com/archive/2008/05/14/448890.aspx
http://technet.microsoft.com/en-us/library/bb201658.aspx

Also use the below mentioned link to use the exchange management shell for managing the queues.

http://technet.microsoft.com/en-us/library/aa998047.aspx

Hope this information will help you.

Have  a nice day.

Author

Commented:
We are monitoring the event log quite closely and are aware of all of the backpressure related events.  I just thought that there was something out there that was like an on-off switch.  It detects that there is a problem and triggers the backpressure.  If I could query that switch, then I can figure out why I didn't get a "normal" event, or that I'm still in backpressure for some reason.
Did you any chance install Exchange 2007 SP1 to resolve the low disc space issue, if yes then it could be possible there are no events.

Because

According to http://technet.microsoft.com/en-us/library/bb201658(EXCHG.80).aspx

"By default, the high level of hard disk drive space utilization is calculated by using the following formula:

100*(hard disk drive size - fixed constant) / hard disk drive size

In the release to manufacturing (RTM) version of Microsoft Exchange Server 2007, the value of fixed constant is 4 GB.

In Microsoft Exchange Server 2007 Service Pack 1 (SP1), the value of fixed constant is 500 MB."


Exchange 2007 sp1 onwards only 500 MB is low disc space unlike RTM also you can use the formula to calculate if you are still facing back pressure.

Author

Commented:
So it sounds like the answer to my question is, no.  I can't ask the exchange server if it is backpressure.  I have to search for the answer in the event logs, etc.

Correct?
Hi,

As i mentioned earlier you can configure the bp as per your requirement and as per your comfort level
http://technet.microsoft.com/en-us/library/bb201658(EXCHG.80).aspx

Thats your control switch.


Yes, you will have to look for events and also you can calculate using formula given in the link.

Author

Commented:
Thanks for the input - points awarded for participation.

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