Our Elasticsearch cluster is used to provide search results for a frontend. Most of the traffic is pretty negligible and the cluster can handle the load just fine. At a scheduled time each week, however, several hundred thousands of newsletters are generated, each containing user-specific content, resulting in a ES query for each of them.
During that time the overall response time of our cluster is degrading significantly. We are looking for ways to mitigate this behavior and came up with the idea of having separate ES nodes for separate query concerns. So node A would be accessed for normal traffic, while node B would be accessed for newsletter queries exclusively. That way node B would only cause a slowdown for newsletter queries, which is fine.
Is a cluster setup like this possible/viable/advisable? Are there better alternatives?