Search Topology Limits

Issue description

This series of Best Practices shows whether the search topology component count is within the official Microsoft guidelines.

Explanation

Exceeding these limits slows down the communication between search components, which can result in longer query latencies and the search not functioning properly.

SPDocKit Best Practice Maximum Supported Value Description
Analytics Processing Components per Search Service Application 6
Analytics Processing Components per Server 1
Analytics Reporting Databases 4 per Search service application This limit is a threshold and can be exceeded to accommodate specific requirements. Create a new database when the size of any of the existing analytics report databases reaches 250 GB or 20 million rows in total.
Content Processing Components 1 per server Although a specific physical host or virtual machine does support multiple content processing components, you achieve better usage of the CPU capacity by using one content processing component.
Crawl Components per Search Service Application 16
Crawl Components per Server 1
Index Components per Search Service Application 60 The number of index components is equal to the number of index partitions multiplied by the number of index replicas.
Index Components per Server 4 The number of index components is equal to the number of index partitions multiplied by the number of index replicas.
Index Partitions 25 per Search service application An index partition is a subset of the search index. Increasing the number of index partitions results in each partition holding a smaller subset of the index, reducing the RAM and disk space that is needed on the servers hosting the index components.
Index Replicas 3 per index partition Each index partition can have a set of replicas. Replicas have a positive effect on query performance and it provides better fault tolerance. However, too many replicas per partition can affect indexing performance.
Link Databases 4 per Search service application The highest tested number of items a link database can contain is 100 million.
Query Processing Components 1 per server
Search Components 64 per Search service application This limit does not include crawl components. The sum of all the other search components must stay within this limit.

Solution

Make sure that the number of components in your search topology is within the supported boundaries. To check your search topology, go to Central Administration > Application Management > Manage service applications > Search Service Application.

Additional Info

Additional information can be found in the following article: