Understanding of solr Shard sharding

solr  Shard sharding

                                             

                                    - shard1

                                                  

collection (logical instance) - shard2

 

                                    - shard3

 

For example, if there are 3 physical machines now, then the data is partitioned according to 3 machines, and each machine is divided into 1/3

Then this part of the data on each machine will be backed up on other machines.