Thanks Shawn and ErickI got the points * Solr does not stored every single piece of information of state.json but can be recreated.
I think there is something not adding up <<<cores should not be erased, though. It should be ignored. This was my assumption earlier. Restarted solr cloud without no collections in zk and got cores directories deleted in disk. *Checked with du and ls The only way I can imagine the data getting deleted on Solr startup is a situation where the collection *is* in ZK and the replicas that are already online are empty. Collections is not in zk, had only 1 replica per shard. Solr nodes were in down state It will be helpful if you can reproduce and suggest. delete /collections in zookeeper and restart solr cloud. On Fri, Jan 11, 2019, 5:36 AM Shawn Heisey <apa...@elyograg.org wrote: > On 1/9/2019 4:25 AM, Yogendra Kumar Soni wrote: > > How to know attributes like shard name and hash ranges with associated > core > > names if we lost state.json file from zookeeper. > > core.properties only contains core level information but hash ranges are > > not stored there. > > > > Does solr stores collection information, shards information anywhere. > > If you completely lose the information in ZooKeeper, SolrCloud will > cease to function properly. Some of that information is not stored > anywhere else. This is why you should have redundancy at the ZK level, > which means a minimum of 3 hosts.Making occasional backups of the ZK > data directory would also a good idea. > > Responding to another thread you started: If you start SolrCloud with > an empty zookeeper, none of the cores relating to collections that are > not found in ZK will start. This is because without the info in ZK, > Solr has no idea how to use those cores. The data contained in those > cores should not be erased, though. It should be ignored. The only way > I can imagine the data getting deleted on Solr startup is a situation > where the collection *is* in ZK and the replicas that are already online > are empty. > > Thanks, > Shawn > >
