Bug 1079763
| Summary: | Some backup won't become passive mode mode when more than two live-backup (e.g. 2 live and 2 backup) is configured with data replication | ||||||
|---|---|---|---|---|---|---|---|
| Product: | [JBoss] JBoss Enterprise Application Platform 6 | Reporter: | Masafumi Miura <mmiura> | ||||
| Component: | HornetQ, Documentation | Assignee: | eap-docs <eap-docs> | ||||
| Status: | CLOSED WONTFIX | QA Contact: | Miroslav Novak <mnovak> | ||||
| Severity: | high | Docs Contact: | Russell Dickenson <rdickens> | ||||
| Priority: | unspecified | ||||||
| Version: | 6.2.1 | CC: | csuconic, msvehla, tanabe.yoshimasa, twells | ||||
| Target Milestone: | --- | ||||||
| Target Release: | EAP 6.4.0 | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2014-11-12 14:56:07 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Attachments: |
|
||||||
|
Description
Masafumi Miura
2014-03-23 23:44:32 UTC
Created attachment 877908 [details]
config files
Hi, I've checked the config and see that there is same backup-group-name "fish" for live1 and live2. Each live/backup pair should have unique backup-group-name. Can you modify the config and try? Thanks, Mirek (In reply to Miroslav Novak from comment #2) > > I've checked the config and see that there is same backup-group-name "fish" > for live1 and live2. Each live/backup pair should have unique > backup-group-name. Can you modify the config and try? > Hi, the HornetQ documentation[1] has the following note: ~~~ A backup-group-name example: suppose you have 5 live servers and 6 backup servers: - live1, live2, live3: with backup-group-name=fish - live4, live5: with backup-group-name=bird - backup1, backup2, backup3, backup4: with backup-group-name=fish - backup5, backup6: with backup-group-name=bird After joining the cluster the backups with backup-group-name=fish will search for live servers with backup-group-name=fish to pair with. Since there is one backup too many, the fish will remain with one spare backup. The 2 backups with backup-group-name=bird (backup5 and backup6) will pair with live servers live4 and live5. ~~~ It indicates that multiple live and backup are able to have same backup-group-name. In addition, as I noted in the previous comment#1, all backup nodes become passive and form live-backup pairs if two backup nodes are started before two live nodes. Therefore, I think "Each live/backup pair should have unique backup-group-name" is not correct. [1] http://docs.jboss.org/hornetq/2.3.0.Final/docs/user-manual/html/ha.html#ha.mode.replicated That's related to shared storage. on Replication you can only have one node and one backup. this is as planned. With Shared storage you can have a lock among the nodes. that's not possible with replication. I would close this and fix the documentation. I just tried scenario: 1. Start 2 live nodes (node1 and node2) 2. Start 1 backup node (node3) 3. Start another backup node (node4) 4. Stop node4 and see the same issue. node4 did not become backup for live node1. node4 does not activate even when live node1 is killed. I can see this to happen. When node3 is started then it becomes backup for live node 1. When node 4 is started then it seems that it starts to replicate journal not from live node 1 but from backup node3 which is already backup for live node 1. So there is replication in this order node1 -> node3 -> node4. Because backup node 4 directly replicates data from backup node 3, it does not become backup for live node 1. I'm not sure if node 4 actually can become backup for node 1 when node 3 is stopped because there could be journal inconsistencies. I don't know the implementation details in this. My apologize, you're right with the community documentation. There is exactly what you say. EAP 6 documentation does not mention this. We should discuss whether it's supported to have multiple backups for 1 live server for replicated journal. This appears to be tricky non-intuitive thing. Implementing this would be a feature... and it won't be easy... I"m not sure we would fix it. I agree with Clebert. This would be a new feature. I suggest to update documentation in this way: a) we support only one backup per live server b) live/backup pair must have unique backup group name and it must be specified (this means we'll not support the random live/backup pairing when backup-group-name is not specified) Adding flags and assigning to doc team. *** Bug 1079765 has been marked as a duplicate of this bug. *** |