Scaling the Solr environment will result in increasing the storage requirements for the index and will likely require adding additional servers. This should be discussed and agreed with the customer as these additional costs need to be paid by the customer.
Adding additional hardware or storage is not only required for providing a high-availability solution for Solr. It can also be useful to avoid performance issues with Solr when shredding the index across several servers is required or when adding a replica of the index is considered if the search demand is high.
It is important to monitor the storage and computing power (CPU/RAM) of the Solr environment over time and to define thresholds for early warnings. Tools such as Splunk facilitate monitoring and can be used to create alert e-mails based on thresholds.
There are many factors that can affect the performance of indexing and searching. It is crucial to ensure that the performance of the Solr environment is acceptable and this can only be confirmed through time.
Solr must be installed on a dedicated server and not shared with other applications.
