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Supporting LOCAL non-HA AS/MQ clustering-mode

- Meeting minutes of 28th July 2006 - attendees: Sivakumar Thyagarajan, George Tharakan, Binod PG

  • how do we achieve the default LOCAL configuration (1:1 AS/MQ cluster) in 9.1EE
  • Master broker required (in the least as a config change record(CCR) repository) for the LOCAL MQ cluster that would be started with the AS cluster.
  • Clarified AS DAS is not necessarily highly available but restartability guaranteed. (AS recommends DAS to be hosted off SunCluster today)
  • Clarified that a master broker cannot serve two MQ clusters. Apparently lots of MQ effort required for this enhancement. So rules out "DAS's embedded broker being the master broker for all AS/MQ auto-clusters in the domain"
  • Clarified that choice of a master broker cannot be changed. We do not have an election mechanism to determine a master broker when a master broker fails. Master broker responsible for holding CCRs of destination/durable subscription metadata and holding CCR change history. No current plans by MQ to implement such a feature as well. So rules out "dynamically an AS cluster instance's broker as a master broker and re-electing on the master broker's failure."
  • Understood that the master broker should not be added in the address list so that master broker is merely used as a CCR repository and not as a message store as well, esp when we want sticky loadbalancing.
  • Left with the following alternatives
  1. DAS to host a master broker jms-service per AS cluster in the domain and start this broker when AS cluster is started. disadv: DAS would potentially host multiple brokers (one EMBEDDED broker and 'n' master brokers for 'n' clusters in that domain) # Select a NA in an AS cluster and host the master broker there. disadv: affected by the designated NA's lifecycle/availability. # A policy where the first cluster instance in a cluster is designated as the master broker. disadv: This instance should atleast guaranteed to have an availablity > other instances in the cluster. # Fall back to 8.1EE mode of operation (no LOCAL auto-AS/MQ clusters by default and clusters are recommended to have REMOTE MQ clusters)