Bernd, When you create a collection via Collections API, the internal logic tries its best to equally distribute the nodes across the shards but sometimes it don't happen.
The best thing about SolrCloud is you can manipulate its cloud architecture on the fly using Collections API. You can delete a replica of one particular shard and add a replica (on a specific machine/node) to any of the shards anytime depending to your design. For the above, you can simply: call DELETEREPLICA api on shard1--->server2:7574 (or the other one) https://cwiki.apache.org/confluence/display/solr/Collections+API#CollectionsAPI-DELETEREPLICA:DeleteaReplica boss ------ shard1 | |-- server2:8983 (leader) | --- shard2 ----- server1:8983 | |-- server5:7575 (leader) | --- shard3 ----- server3:8983 (leader) | |-- server4:8983 | --- shard4 ----- server1:7574 (leader) | |-- server4:7574 | --- shard5 ----- server3:7574 (leader) |-- server5:8983 call ADDREPLICA api on shard1---->server1:8983 https://cwiki.apache.org/confluence/display/solr/Collections+API#CollectionsAPI-DELETEREPLICA:DeleteaReplica boss ------ shard1 ----- server1:8983 | |-- server2:8983 (leader) | --- shard2 ----- server1:8983 | |-- server5:7575 (leader) | --- shard3 ----- server3:8983 (leader) | |-- server4:8983 | --- shard4 ----- server1:7574 (leader) | |-- server4:7574 | --- shard5 ----- server3:7574 (leader) |-- server5:8983 Hope this helps. Amrit Sarkar Search Engineer Lucidworks, Inc. 415-589-9269 www.lucidworks.com Twitter http://twitter.com/lucidworks LinkedIn: https://www.linkedin.com/in/sarkaramrit2 On Mon, May 8, 2017 at 5:08 PM, Bernd Fehling < bernd.fehl...@uni-bielefeld.de> wrote: > My assumption was that the strength of SolrCloud is the distribution > of leader and replica within the Cloud and make the Cloud somewhat > failsafe. > But after setting up SolrCloud with a collection I have both, leader and > replica, on the same shard. And this should be failsafe? > > o.a.s.h.a.CollectionsHandler Invoked Collection Action :create with params > replicationFactor=2&routerName=compositeId&collection.configName=boss& > maxShardsPerNode=1&name=boss&router.name=compositeId&action= > CREATE&numShards=5 > > boss ------ shard1 ----- server2:7574 > | |-- server2:8983 (leader) > | > --- shard2 ----- server1:8983 > | |-- server5:7575 (leader) > | > --- shard3 ----- server3:8983 (leader) > | |-- server4:8983 > | > --- shard4 ----- server1:7574 (leader) > | |-- server4:7574 > | > --- shard5 ----- server3:7574 (leader) > |-- server5:8983 > > From my point of view, if server2 is going to crash then shard1 will > disappear and > 1/5th of the index is missing. > > What is your opinion? > > Regards > Bernd > > > >
