1. You could just have 2 VMs, one has all 20 shards of your collection, the other one has the replicas for those shards. In this scenario, if one VM is not available, you still have application availability as at least one replica is available for each shard. This assumes that your VM can fit all the data in one VM (all 20 shards) without compromising on performance or getting into memory or garbage collection issues (I am not sure what the size of your collection or shards is). For additional redundancy, you can add another VM and add another replica for for all your shards.
2. Can you provide more specifics around what sort of issues are you thinking of? Replication in general is pretty solid in the version you are talking about. You could comb through JIRA ( https://issues.apache.org/jira/browse/SOLR-5821?jql=project%20%3D%20SOLR%20AND%20status%20in%20(Open%2C%20%22In%20Progress%22%2C%20Reopened)%20AND%20text%20~%20%22replica%22 ) 3. I would recommend you take a look at the Solr Collection API ( https://lucene.apache.org/solr/guide/6_6/collections-api.html). Parameters that you want to pay more attention to are "replicationFactor", "numShards" and "maxShardsPerNode" that relate to the shards and replicas. If you have a use case that warrants you to go beyond the above scenario of having all shards on the same VM, then you should read more into "maxShardsPerNode", etc. - but perhaps you can share a bit more around that use that. Thanks, -- Sameer Maggon https://www.searchstax.com | Solr-as-as-Service platform on AWS, Azure and GCP On Sat, Jan 27, 2018 at 2:08 AM, SOLR4189 <klin892...@yandex.ru> wrote: > I use SOLR-6.5.1. I would like to use SolrCloud replicas. And I have some > questions: > > 1) What is the best architecture for this if my collection contains 20 > shards, and each shard is in different vm? 40 vms where 20 for leaders and > 20 for replicas? Or maybe stay with 20 vms where leader and replica (of > another leader) in the same vm but to add RAM? > > 2) What are opened issues about replicas in SOLR-6.5.1 that I need to > check? > > 3) If I use SolrCloud replica, which configuration parameters should I > change? Which can I change? > > > > -- > Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html
