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cluster-computingibm-mqnfs

Does Multi-instance queue manager work fine in an MQ cluster with hybrid file system including NFS4 & NFS3

We have defined a WebSphere MQ cluster in our Production infrastructure with all the file systems using shared Network storage (NFS3). Recently we had to make one of the cluster queue managers in the MQ cluster highly available. So we migrated two of the servers in the MQ cluster to NFS4 and redefined the queue manager in multi-instance mode with active instance of QM in one server and the stand-by QM in the other server(both servers has NFS4 as file system). Now the question we have is since MQ cluster has lot of inter cluster communication happening between queue managers all time is it a best practice to keep MI queue managers in a cluster which has hybrid file systems including NFS4 & NFS3? Does the hybrid file system cause any known issues on our MI queue managers when we try to switch them?

Solution

  • Please see Requirements for shared file systems in the IBM Knowledge Center for full details. Short answer: MQ may run on NFS3 but the functionality and reliability you probably expect from it isn't there.

    If a queue manager fails, or if there is a communication failure with the file system, files locked by the queue manager need to be unlocked and made available to other processes without waiting for the queue manager to be reconnected to the file system.

    For multi-instance queue managers on Microsoft Windows, the networked storage must be accessed by the Common Internet File System (CIFS) protocol used by Microsoft Windows networks.

    For multi-instance queue managers on other supported platforms, the storage must be accessed by a network file system protocol which is Posix-compliant and supports lease-based locking. Network File System Version 4 satisfies this requirement. Older file systems, such as Network File System Version 3, which do not have a reliable mechanism to release locks after a failure, must not be used with multi-instance queue managers.

    The file system supporting Multi-Instance QMgrs must be NFS4 or better. The possible instability issue isn't from running a hybrid mixed NFS3/4 setup, but rather from any use of NFS3 at all with MIQM.