You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@qpid.apache.org by "Alan Conway (JIRA)" <ji...@apache.org> on 2010/10/04 15:40:32 UTC
[jira] Resolved: (QPID-2220) Assisting manual recovery from a
complete persistent cluster crash.
[ https://issues.apache.org/jira/browse/QPID-2220?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alan Conway resolved QPID-2220.
-------------------------------
Resolution: Won't Fix
Revision 931185 adds cluster-qpid-store, a tool for manually marking a store clean after a total cluster crash where there is no clear "last member". Adding a counter to further automate handling this case adds complexity and possible performance impact that does not seem justified at the moment.
> 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 Persistence ID, a 64 bit value that is incremented for each enqueue, dequeue. If the cluster stores (config-change,PID) pairs then in recovery we can use actual-PID - config-change PID as a tiebreaker.
> Proposed change to MessageStore API:
> /** Returns a monotonically increasing value reflecting 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.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project: http://qpid.apache.org
Use/Interact: mailto:dev-subscribe@qpid.apache.org