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RCAMAXConcurrency & MAPI Session limit dependency RRS feed

  • Question

  • I'm facing the MAPI session limit exceed the 32 limit error.. after a auto database failover.

    My Mailbox servers ( 2010 environment) are left with the default configuration, and the RCAMaxConcurreny on the throttling policy is set to 100.

    RCA Max Concurrency is the one which controls the RPC session initiated by outlook ? if so, am I allowing 100 sessions on the client access server, where the Mailbox servers are restricted with 32 limit ?

    any help in knowing why this session exceed error only when the auto database failover occured?

    Monday, March 17, 2014 3:11 AM

All replies

  • I believe that most of what you are looking for is described in http://technet.microsoft.com/en-us/library/dd298094(v=exchg.141).aspx

    The RCAMaxConcurrency parameter indicates how many concurrent connections an RPC Client Access user can have against a server running Exchange 2010 at one time. The default value is 20.

    However, you may be hitting the session limits defined at the Exchange Store (http://technet.microsoft.com/en-us/library/ff477612(v=exchg.141).aspx) or at the Client Access (http://technet.microsoft.com/en-us/library/ff629384(v=exchg.141).aspx)

    I would suspect it could be both, so you may want to increase both, assuming you believe that these are valid sessions and not wildly out-of-control, unsecured clients creating these sessions. 

    So look at increasing the "Maximum Allowed Sessions Per User" registry key and throttling policy (as needed)

    DaDougInc

    Wednesday, March 19, 2014 5:29 PM
  • Hi Rajkumar,

    Totally agree with DaDougInc.

    According to the article on Technet (http://technet.microsoft.com/en-us/library/dd298094(v=exchg.141).aspx), I found detailed information on the RcaMaxConcurrency Paramenter:

    The RcaMaxConcurrency parameter specifies how many concurrent connections an RPC Client Access user can have against a server running Exchange 2013 at one time.

    Based on my research, the MAPI session limit can't be changed, Default number of user sessions per server is 32.

    More details in the following article:

    Exchange Store Limits

    http://technet.microsoft.com/en-us/library/ff477612(v=exchg.141).aspx

     

    Thanks

    Mavis


    Mavis Huang
    TechNet Community Support

    Thursday, March 20, 2014 9:28 AM
  • Thank you DaDougInc & Mavis,

    If I have edited the Throttling Policy of RCAMAXConcurrency from 20 to 100.. with no change on the MAPI session limit, will that impact me in any way?

    I experienced an issue, where the get-mailboxlogonstatistics of a user shows a count of 78.. and he is not able to access his mailbox, and event 9646 occurred for that mailbox in mailbox server..

    Is that because of Im allowing more RPC sessions at the CAS server and its restricted with 32 session on the Mailbox servers ?

    Thursday, March 20, 2014 1:51 PM
  • Hi DaDougInc & Mavis,

    Please share your ideas on this..

    If I have edited the Default Throttling Policy of RCAMAXConcurrency from 20 to 100.. with no change on the MAPI session limit at mailbox server, will that impact me in any way?

    I experienced an issue, where the get-mailboxlogonstatistics of a user shows a count of 78.. and he is not able to access his mailbox, and event 9646 occurred for that mailbox in mailbox server..

    Is that because of I'm allowing more RPC sessions at the CAS server and its restricted with 32 MAPI session on the Mailbox servers ?

    Thursday, March 27, 2014 8:02 PM