How does Jira nodes in the cluster do Lucene replication

[Dhruv Joshi]

Hello,

I wanted to understand how Jira nodes in the Cluster do Lucene replication?

And how does other nodes in the jira knows there is an update with one node and other nodes copy that information in it's own indexing.

Also how does write.lock file comes into this picture ?

Thanks,

Dhruv

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

Short answer is that it doesn't.  Each node has its own local index and updates that locally when the node spots that the database has been updated.

The write.lock file is mainly there to prevent a node trying to make simultaneous edits in different threards.

[Marc - Devoteam]

Hi @Dhruv Joshi 

The cluster topology is for multiple active servers with the following characteristics: 

• The Jira instances share a single relational database instance.
• The Lucene Index is replicated in almost real time and a copy kept local to each instance.
• The Attachments are held in a shared location.
• The Jira instances will keep their internal data caches consistent.
• Multiple instances may be active at any one time.
• Cluster-wide locks are available.
• A load balancer will need to be configured to share requests between all active nodes in the cluster
  • The load balancer will not direct any requests to a node that is not active and redirect all requests for a session to the same node
• Active servers will:
  • Process web requests.
  • Process background and recurring tasks. Scheduled tasks may be configured to run on one or all instances in the cluster.
  • In all practical ways behave exactly the same as a standalone Jira server.
• Passive servers:
  • Do not process web requests.
  • Do not run any background or recurring tasks.
  • Are in a state so that they are able to take over the workload in the shortest amount of time, i.e all plugins loaded, Lucene index up to date, etc.

Write.lock issues can have multiple issues.

- Restart of nod that is not completing
- Plugin (App) update fails on a node

There are open features to make write lock problems more visible, see:

JRASERVER-66596 and JRASERVER-65890