Hi Jan, Comments inline:
On Tue, Jun 12, 2018 at 2:19 AM Jan Høydahl <jan....@cominvent.com> wrote: > Hi > > I'm trying to have Autoscaling move a shard to another node after manually > splitting. > We have two nodes, one has a shard1 and the other node is empty. > > After SPLITSHARD you have > > * shard1 (inactive) > * shard1_0 > * shard1_1 > > For autoscaling we have the {"minimize" : "cores"} cluster preference > active. Because of that I'd expect that Autoscaling would suggest to move > e.g. shard1_1 to the other (empty) node, but it doesn't. Then I create a > rule just to test {"cores": "<2", "node": "#ANY"}, but still no > suggestions. Not until I delete the inactive shard1, then it suggests to > move one of the two remaining shards to the other node. > > So my two questions are > 1. Is it by design that inactive shards "count" wrt #cores? > I understand that it consumes disk but it is not active otherwise, > so one could argue that it should not be counted in core/replica rules? > Today, inactive slices also count towards the number of cores -- though technically correct, it is probably an oversight. > 2. Why is there no suggestion to move a shard due to the "minimize cores" > reference itself? > The /autoscaling/suggestions end point only suggests if there are policy violations. Preferences such as minimize:cores are more of a sorting order so they aren't really being violated. After you add the rule, the framework still cannot give a suggestion that satisfies your rule. This is because even if shard1_1 is moved to node2, node1 still has shard1 and shard1_0. So the system ends up not suggesting anything. You should get a suggestion if you add a third node to the cluster though. Also see SOLR-11997 <https://issues.apache.org/jira/browse/SOLR-11997> which will tell users that a suggestion could not be returned because we cannot satisfy the policy. There are a slew of other improvements to suggestions planned that will return suggestions even when there are no policy violations. > > -- > Jan Høydahl, search solution architect > Cominvent AS - www.cominvent.com > > -- Regards, Shalin Shekhar Mangar.