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https://issues.apache.org/jira/browse/QPID-2220?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alan Conway updated QPID-2220:
------------------------------

    Summary: Assisting manual recovery from a complete persistent cluster 
crash.  (was: Assisign manual recovery from a complete persistent cluster 
crash.)

> Assisting manual recovery from a complete persistent cluster crash.
> -------------------------------------------------------------------
>
>                 Key: QPID-2220
>                 URL: https://issues.apache.org/jira/browse/QPID-2220
>             Project: Qpid
>          Issue Type: Improvement
>          Components: C++ Broker
>    Affects Versions: 0.5
>            Reporter: Alan Conway
>            Assignee: Alan Conway
>
> If every member of a persistent cluster crashes then manual intervention is 
> required to identify which store is most up-to-date, so it can be used to 
> recover. We need to provide tools to assist in this identification.
> The cluster can save a config-change counter with each config change (cluster 
> membership change). In recovery, the broker with the highest config-change 
> counter has the best store. However if the last brokers in the cluster crash 
> so close together that none can record a config-change we need an additional 
> decider.
> The store at http://qpidcomponents.org/download.html#persistence maintains a 
> global Record Identifier (RID), a 64 bit value that is incremented for each 
> enqueue and dequeue. If the cluster stores  (config-change,RID) pairs then in 
> recovery we can use actual-RID - RID at config-change as a tiebreaker.
> Proposed change to MessageStore API:
>   /** Returns a monotonically increasing value reflecting the number of 
> changes to the store.
>   * The value can wrap-around to 0.
>   * Stores need not implement this function, they can simply return 0.
>   */
>   uint64_t getChangeCounter();
> The default implementation just returns 0  and the cluster must fall back to 
> relying on config-change counts.

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