In my case, when trying on Solr7.4 (in response to Shawn Heisey's 6/19/18 comment "If this is a provable and reproducible bug, and it's still a problem in the current stable branch"), I had only installed Solr7.4 on one host, and so I was testing with two nodes on the same host (different port numbers). I had previously had the same symptom when the two nodes were on different hosts, but that was with Solr6.6 -- I can try it again with Solr7.4 with two hosts and report back.
-----Original Message----- From: Shawn Heisey [mailto:apa...@elyograg.org] Sent: Tuesday, July 31, 2018 2:26 PM To: solr-user@lucene.apache.org Subject: Re: sharding and placement of replicas On 7/27/2018 8:26 PM, Erick Erickson wrote: > Yes with some fiddling as far as "placement rules", start here: > https://lucene.apache.org/solr/guide/6_6/rule-based-replica-placement.html > > The idea (IIUC) is that you provide a snitch" that identifies what > "rack" the Solr instance is on and can define placement rules that > define "don't put more than one thingy on the same rack". "Thingy" > here is replica, shard, whatever as defined by other placement rules. I'd like to see an improvement in Solr's behavior when nothing has been configured in auto-scaling or rule-based replica placement. Configuring those things is certainly an option, but I think we can do better even without that config. I believe that Solr already has some default intelligence that keeps multiple replicas from ending up on the same *node* when possible ... I would like this to also be aware of *hosts*. Craig hasn't yet indicated whether there is more than one node per host, so I don't know whether the behavior he's seeing should be considered a bug. If somebody gives one machine multiple names/addresses and uses different hostnames in their SolrCloud config for one actual host, then it wouldn't be able to do any better than it does now, but if there are matches in the hostname part of different entries in live_nodes, then I think the improvement might be relatively easy. Not saying that I know what to do, but somebody who is familiar with the Collections API code can probably do it. Thanks, Shawn
