Solr vs SolrCloud

[#1]

Hi All,

I am bit confused with Solr and Solrcloud

Why would anyone use Solr and not Solrcloud, as Solrcloud gives it all the HA functionality

Also as it is recommended to run Solr clusters separately from HDP clusters, does this same applies to Solrcloud also.

SolrCloud works with HDFS and not Solr, if we run it in separate cluster then is there any use of using HDFS?

Thanks,

Avijeet

[#2]

Thanks @Cassandra Targett, so is it right to say, there are 3 modes

1. Solr standalone mode

2. master/slave

3. SolrCloud

I assume the configuration is different for each type of setup.

[#3]

When speaking about scaling capabilities of Solr, there are really only two modes:

1. Master/slave, which is one or more Solr servers running in standalone mode with what the community calls "legacy scaling" features enabled.

2. SolrCloud, which is one or more Solr servers running with ZooKeeper coordinating activity between them.

Solr doesn't make the two really obvious, meaning there's no single switch to turn on or off to choose which mode. Both are a set of configuration options that are different depending on the mode you want to use.

It's important to note master/slave is not really different from standalone mode because you can work for years with Solr running on a single server and then add index replication (and/or distributed queries) if you need it. It's harder to move from standalone to SolrCloud (although not impossible).

Some documentation from the Solr Reference Guide might help:

Master/Slave: https://cwiki.apache.org/confluence/display/solr/Legacy+Scaling+and+Distribution

SolrCloud: https://cwiki.apache.org/confluence/display/solr/SolrCloud

[#4]

Does streaming expressions in solr8.x work in a master/slave setup outside of Solr cloud?