There are advantages and disadvantages of using a master-slave
replication.
A system with master-slave index replication offers the following advantages and disadvantages:
Advantages
- Splits read and write load and operations
- Load distribution for search queries
- High availability for searching
- Any number of slave instances can be created to scale query performance
- Usually less frequent index updates on the slaves and better use of the cache
Disadvantages
- Increased latency (sum of tracking and Solr replication latency)
- Occasional large IO load to replicate large merges
- Complicated load balance and management
- Reconfiguration if the master is lost