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    Clearing WebSphere MQ shared memory resources - Middleware News

    Saturday, August 18, 2012, 11:51 AM
    Categories: WebSphere MQ
    Posted By: Karthick

    When a WebSphere MQ queue manager is ended normally, the queue manager removes the majority of the IPC resources that it was using. A small number of IPC resources remain and this is as designed: some of the IPC resources are intended to persist between queue manager restarts. The number of IPC resources remaining varies to some extent, depending on the operating conditions.End of change
    Start of changeThere are some situations when a larger proportion of the IPC resources in use by a queue manager might persist after that queue manager has ended:

        If applications are connected to the queue manager when it stops (perhaps because the queue manager was shut down using endmqm -i or endmqm -p), the IPC resources used by these applications might not be released.
        If the queue manager ends abnormally (for example, if an operator issues the system kill command), some IPC resources might be left allocated after all queue manager processes have terminated.

    In these cases, the IPC resources are not released back to the system until you restart (strmqm) or delete (dltmqm) the queue manager. End of change

    Start of changeIPC resources allocated by WebSphere MQ are maintained automatically by the allocating queue managers. You are strongly recommended not to perform manual actions on or remove these IPC resources. End of change

    Start of changeHowever, if it is necessary to remove IPC resources owned by mqm, follow these instructions. WebSphere MQ provides a utility to release the residual IPC resources allocated by a queue manager. This utility clears the internal queue manager state at the same time as it removes the corresponding IPC resource. Thus, this utility ensures that the queue manager state and IPC resource allocation are kept in step. To free residual IPC resources, follow these steps:End of change
    Start of changeStart of change

        End the queue manager and all connecting applications.
        Log on as user mqm.
        Type the following:
        On Solaris, HP-UX, and Linux:

        /opt/mqm/bin/amqiclen -x -m QMGR

        On AIX:

        /usr/mqm/bin/amqiclen -x -m QMGR

        This command does not report any status. However, if some WebSphere® MQ-allocated resources could not be freed, the return code is nonzero.
        Explicitly remove any remaining IPC resources that were created by user mqm.

    End of change
    Note: Start of changeIf a non-mqm application attempted to connect to WebSphere MQ before starting any queue managers, there might still be some WebSphere MQ IPC resources remaining even after following the above steps. These remaining resources were not created by user mqm and there is no straightforward way to reliably recognize them. However, these resources are very small and are reused when WebSphere MQ is next restarted.End of change
    0 (0 Ratings)

    SSL CipherSpecs supported by IBM WebSphere MQ - Middleware News

    Saturday, August 18, 2012, 11:49 AM
    Categories: WebSphere MQ
    Posted By: Karthick

    The following table lists the CipherSpecs supported by WebSphere MQ. Specify the CipherSpec name in the SSLCIPH property of the SVRCONN channel on the queue manager and in MQEnvironment.SSLCipherSpec

    Table 1. Supported CipherSpecsCipherSpec

    DES_SHA_EXPORT
    DES_SHA_EXPORT1024
    NULL_MD5
    NULL_SHA
    RC2_MD5_EXPORT
    RC4_56_SHA_EXPORT1024
    RC4_MD5_US
    RC4_MD5_EXPORT
    RC4_SHA_US
    TRIPLE_DES_SHA_US
    0 (0 Ratings)

    AMQ9213 2009 MQRC_CONNECTION_BROKEN on IBM MQ clients - Middleware News

    Thursday, August 2, 2012, 8:31 AM
    Categories: WebSphere MQ
    Posted By: Karthick

    You have WebSphere MQ clients which connect to several different MQ servers. The MQ clients are quite frequently disconnected with rc=2009, MQRC_CONNECTION_BROKEN. The clients are able to reconnect immediately. The queue managers are running well. You see no problems when issuing 'runmqsc' commands on the server.

    Symptom

    On the MQ server side you see the following message in the queue manager's error log, AMQERR01.LOG:

    AMQ9213: A communications error for TCP/IP occurred.
    EXPLANATION: An unexpected error occurred in communications.
    ACTION: The return code from the TCP/IP(select) [TIMEOUT] 660 seconds call was 11 (X'B'). Record these values and tell the systems administrator.

    Cause

    There was a parameter recently added in your qm.ini file called ClientIdle that was set to 600 secs. This caused the client connections to end after they were idle for the specified period of time + 60 seconds. After the connection is terminated at the server, the next attempt to send a request from the client side results in rc=2009.

    Resolving the problem

    You can either remove the ClientIdle parameter from the Channels stanza of your qm.ini files or you can set it to a value, which is higher than you expect your clients will be idle between calls. 
    The default path for the qm.ini file is /var/mqm/QMGRs//
    3.7 (1 Ratings)

    IBM Leap Second may cause Linux to freeze

    Tuesday, July 24, 2012, 12:01 AM
    Categories: WebSphere MQ
    Posted By: Karthick

    After adding the leap second in Linux on 30 June, 2012, your WebSphere MQ queue manager has many FDC files related to resource issues or constraints and they will commonly report rc=xecP_E_NO_RESOURCE. You may also see your queue manager hang or freeze or there may be high cpu. The FDC's are being generated on a daily basis and may have probes of XY348010 or XC272003 from xcsCreateThread but there could be other FDC's with different probes also.

    Content

    On 30 June, the Network Time Protocol (NTP) daemon scheduled a leap second to occur at midnight, meaning that the final minute of the day was 61 seconds long. We have seen several problems with otherwise unexplainable high CPU usage on Linux systems caused by the leap second at the end of June.

    WebSphere MQ does not directly make calls which experience the problem, but we do use the pthreads library (NPTL), which in turn uses futexes ("fast userspace mutexes"), which can hit this problem. Busy systems running WebSphere MQ and other products are susceptible to this problem. You can read more about the problem at these links:

    Anyone else experiencing high rates of Linux server crashes during a leap second day?

    Leap Seconds in Red Hat Enterprise Linux

    Leap second: Linux can freeze

    This problem is solved by either applying Operating System (Linux) patches, resetting the date or rebooting the system. The resolution is dependent on your level of Linux and your environment. Please consult your Linux provider for details of the solution appropriate for your system.

    As a workaround you can follow these steps

    1. Check the Linux kernel version. In theory only 2.6.22 and newer levels should be affected:
      All: uname -r
    2. Switch to root or log in as root at the console
    3. Check to see if NTP is running:
      RHEL: service ntpd status
      SLES: /etc/init.d/ntp status
    4. If NTP is running, disable it:
      RHEL: service ntpd stop
      SLES: /etc/init.d/ntp stop
    5. Set the system clock to the current time:
      All sntp -P no -r pool.ntp.org
      Or: ntpdate 0.us.pool.ntp.org
    6. If NTP was running, reenable it:
      RHEL: service ntpd start
      SLES: /etc/init.d/ntp start
    0 (0 Ratings)

    Migrating to IBM WebSphere MQ for AIX Version 7.0 - Middleware News

    Tuesday, July 10, 2012, 9:58 AM
    Categories: WebSphere MQ
    Posted By: Karthick

    If you want to migrate to WebSphere MQ Version 7.0, complete this task.

    If you migrate from a previous level of this product without first backing up your system, you cannotrevert to your previous level, so back up your system before you install WebSphere MQ Version 7.0. You can then back out the upgrade if necessary. If you back out the upgrade, however, you cannot recover any work, such as changes to messages and objects, performed by WebSphere MQ Version 7.0.

    Procedure

    1. Stop all MQ applications on the machine and the applications accessing remote machines.
    2. End all WebSphere MQ activity.
      1. Log in as a user in group mqm.
      2. Start of changeUse the dspmq command to display the state of all the queue managers on the system.End of change
      3. Use the endmqm command to stop all running queue managers.
      4. Stop any listeners associated with the queue managers, using the command:
        endmqlsr -m QMgrName
      5. To check that you have stopped all of them, enter the following:
        ps -ef | grep mq
        Check that there are no processes listed that are running command lines beginning amq orrunmq. Ignore any that start with amqi.
    3. Log in as root.
    4. Function supplied by the SupportPacs in Table 1 has been superseded by function in WebSphere MQ Version 7.0. Remove these SupportPacs before installing WebSphere MQ Version 7.0.
      Table 1. SupportPacs superseded by WebSphere MQ Version 7.0
      SupportPac NumberDescription
      MA0Y WebSphere MQ Bridge for HTTP
      Note: If you installed SupportPac MACS, remove the directory /usr/mqm/inc64 and its contents.
      Review any other installed SupportPacs for their applicability to WebSphere MQ Version 7.0.
    5. Start of change If you are migrating from WebSphere MQ Version 5.3 to WebSphere MQ Version 7.0, you must uninstall WebSphere MQ Version 5.3. If you are migrating from WebSphere MQ Version 6.0 to WebSphere MQ Version 7.0, you do not have to uninstall WebSphere MQ because the installation process does it for you. However, when migrating from WebSphere MQ Version 6.0 to WebSphere MQ Version 7.0, before installing you must ensure that you manually remove the file sets which have been retired from WebSphere MQ Version 7.0.
      • Remove the following file sets before migrating from WebSphere MQ Version 6.0 to WebSphere MQ Version 7.0:
        • mqm.msg.De_DE
        • mqm.msg.Es_ES
        • mqm.msg.Fr_FR
        • mqm.msg.It_IT
      End of change
    6. Install WebSphere MQ Version 7.0 by following the tasks set out in Start of changeInstalling a WebSphere MQ serverEnd of change.
    7. Restart WebSphere MQ.
    0 (0 Ratings)

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