Summary

During plugin (add-on) installs/updates/delete/disable action UPM will flush the large number of caches (see JRASERVER-64908).
For Jira datacenter this cache flush will be propagated to other nodes, thus affecting them. Also cache flush is triggered during node startup as UPM needs to register and load modules from plugins.

Environment

• Jira datacenter

Steps to Reproduce

1. Upgrade plugin (or start node)
2. Check performance

Expected Results

• Starting new node will not have significant impact for cluster
• Plugin action will not cause cache flush to be propagated to other nodes, only plugin events.
  • Plugin action will have performance impact due to JRASERVER-64908 and nature of action, but it will be isolated

Actual Results

• Starting new node has significant impact for cluster
• Plugin action causes cache flush to be propagated to other nodes, making cluster wide replication storm and putting extra load to DB.

Notes

None

Workaround

• Please plan any plugin actions updates/delete/disable (UPM actions) during low peak hours or maintenance windows.
• Please plan node start-up during low peak hours or maintenance windows (start one node at a time).