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RCAMaxConcurrency Throttling Question RRS feed

  • Question

  • We are using E2k10, but all of our users (roughly 500) are still on Outlook 2k3 and we are not looking to go to 2k10 until Q4 this year.  We are receiving the The connection to the Microsoft Exchange server in unavailable. Outlook must be online or connected to complete this action error for people who have multiple shared calendars.  I know that the fix is to create a new RCAMaxConcurrency throttling policy, set it to 100 and apply it to the users who are having the issue.  The problem I am running into is that a majority of the users are having this issue.  My question is, what would the side effects of changing the default throttling policy to 100 so that all users inherit the setting.  I am thinking that it wouldn’t cause too much of an issue, but wanted to get some feedback before pulling the trigger.  Any thoughts?

    Thank you in advance,

    --Scott


    • Edited by slrobb Friday, April 20, 2012 3:51 PM
    Friday, April 20, 2012 3:51 PM

Answers

  • First off it would be much better to create a new policy and then assign some or all users to that rather than changing the default policy. Example:

    New-ThrottlingPolicy
    -Name "sec-throttling-policy" -RCAMAXConcurrency: 100

     

    Assign to one user

    set-mailbox
    -identity "dom.local/users/JoeSoap" -throttlingpolicy
    "sec-throttling-policy"

     

    Assign to all users

    Get-Mailbox | Set-ThrottlingPolicy -Identity "sec-throttling-policy"

    You don't say how many servers you have but assuming it is just one then you would probably be fine if you only have 500 users. If the users are using excessive resources they would run into the 32 Mapi session limit before taking down your server, see http://support.microsoft.com/kb/980049 .

    For logging setup a counter for RPC Requests and RPC Average Latency - http://technet.microsoft.com/en-us/library/ff367877.aspx . Microsoft says the RPC Requests should be under 40, on a typical server you will see spikes above this but once it is not over 100 there should be no issues.

    • Marked as answer by slrobb Monday, April 23, 2012 2:13 PM
    Saturday, April 21, 2012 7:47 AM

All replies

  • First off it would be much better to create a new policy and then assign some or all users to that rather than changing the default policy. Example:

    New-ThrottlingPolicy
    -Name "sec-throttling-policy" -RCAMAXConcurrency: 100

     

    Assign to one user

    set-mailbox
    -identity "dom.local/users/JoeSoap" -throttlingpolicy
    "sec-throttling-policy"

     

    Assign to all users

    Get-Mailbox | Set-ThrottlingPolicy -Identity "sec-throttling-policy"

    You don't say how many servers you have but assuming it is just one then you would probably be fine if you only have 500 users. If the users are using excessive resources they would run into the 32 Mapi session limit before taking down your server, see http://support.microsoft.com/kb/980049 .

    For logging setup a counter for RPC Requests and RPC Average Latency - http://technet.microsoft.com/en-us/library/ff367877.aspx . Microsoft says the RPC Requests should be under 40, on a typical server you will see spikes above this but once it is not over 100 there should be no issues.

    • Marked as answer by slrobb Monday, April 23, 2012 2:13 PM
    Saturday, April 21, 2012 7:47 AM
  • How any calendars do these users have open at one time? Do you have any 2915 events in the App log of your CAS?


    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Saturday, April 21, 2012 1:46 PM
  • Hi,

    Any update ?


    Wendy Liu

    TechNet Community Support

    Monday, April 23, 2012 7:39 AM
  • Hi,

    Any update ?


    Wendy Liu

    TechNet Community Support


    On Friday, I just modified the default policy and changed the value from 20 to 50.  It looks to have solved the issues, so I am going to set the default back to 20, create a new throttling policy and apply that to all users.
    Monday, April 23, 2012 2:13 PM
  • It is important to understand why it is happening in the first place. Creating a new throttling policy may be a fix for certain cases, but I wouldn't want to see it used as a Band-Aid long-term as this may just prolong an ongoing issue in the background which actually needs fixing.

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Monday, April 23, 2012 9:16 PM
  • I had exactly the same thing.  At the time nobody seemed to know anything about this error and I was puilling my hair out for months.  I edited the default throttling policy but allowed an unlimited amount if mapi connections, this resolved the issues for quite some time but now we are seeing lots of slow reports in Outlook.  looks like users are overloading the Exchange 2010 servers.  Don't know the best way forward really as we have around 4000 Outlook 2003 users.

    Tuesday, April 24, 2012 10:51 AM
  • So the issue reared its ugly head again yesterday.  The following solution has worked so far:

    1. I took a screenshot of the shared calendars that the users had in thier Outlook
    2. I closed Outlook
    3. I opened up outlook with the resetnavpane switch (start > run then typed outlook.exe /resetnavpane)
      • This will remove all of the shared calendars for that user
    4. I then manually added back all of his shared calendars

    I have done this for mutiple users now and it seems to be a solid solution.  I can't wait till our management pulls the trigger on upgrading to Office 2010.  A lot of issues will be resolved, but for now, apply duct tape as needed :)  I hope that this helps.

    Tuesday, April 24, 2012 4:03 PM
  • Nice Solution :)
    Tuesday, July 2, 2013 7:44 PM