How long do the queue manager repositories retain information?
Queue manager repositories retain information for 30 days. An automatic process efficiently refreshes information that is being used.
When a queue manager sends out some information about itself, the full and partial repository queue managers store the information for 30 days. Information is sent out, for example, when a queue manager advertises the creation of a new queue. To prevent this information from expiring, queue managers automatically resend all information about themselves after 27 days. If a partial repository sends a new request for information part way through the 30 day lifetime, the expiry time remains the original 30 days.
When information expires, it is not immediately removed from the repository. Instead it is held for a grace period of 60 days. If no update is received within the grace period, the information is removed. The grace period allows for the fact that a queue manager might have been temporarily out of service at the expiry date. If a queue manager becomes disconnected from a cluster for more than 90 days, it stops being part of the cluster. However, if it reconnects to the network it becomes part of the cluster again. Full repositories do not use information that has expired to satisfy new requests from other queue managers.
Similarly, when a queue manager sends a request for up-to-date information from a full repository, the request lasts for 30 days. After 27 days IBM MQ checks the request. If it has been referenced during the 27 days, it is refreshed automatically. If not, it is left to expire and is refreshed by the queue manager if it is needed again. Expiring requests prevents a buildup of requests for information from dormant queue managers.
Note: For large clusters, it can be disruptive if many queue managers automatically resend all information about themselves at the same time. See Refreshing in a large cluster can affect performance and availability of the cluster. Parent topic: Designing clusters
Related concepts