You are viewing a plain text version of this content. The canonical link for it is here.
Posted to oak-issues@jackrabbit.apache.org by "Michael Marth (JIRA)" <ji...@apache.org> on 2015/03/10 19:09:40 UTC
[jira] [Updated] (OAK-1453) MongoMK failover support for replica
sets (esp. shards)
[ https://issues.apache.org/jira/browse/OAK-1453?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Michael Marth updated OAK-1453:
-------------------------------
Fix Version/s: (was: 1.2)
1.4
> MongoMK failover support for replica sets (esp. shards)
> -------------------------------------------------------
>
> Key: OAK-1453
> URL: https://issues.apache.org/jira/browse/OAK-1453
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: mongomk
> Reporter: Michael Marth
> Labels: production, resilience
> Fix For: 1.4
>
>
> With OAK-759 we have introduced replica support in MongoMK. I think we still need to address the resilience for failover from primary to secoandary:
> Consider a case where Oak writes to the primary. Replication to secondary is ongoing. During that period the primary goes down and the secondary becomes primary. There could be some "half-replicated" MVCC revisions, which need to be either discarded or be ignored after the failover.
> This might not be an issue if there is only one shard, as the commit root is written last (and replicated last)
> But with 2 shards the the replication state of these 2 shards could be inconsistent. Oak needs to handle such a situation without falling over.
> If we can detect a Mongo failover we could query Mongo which revisions are fully replicated to the new primary and discard the potentially half-replicated revisions.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)