Is it good practise to create Query Processing components and Index partitions in WFE servers

Question

What is the best practices for creating query components and index components?

I have the following SharePoint servers in a farm and I have plan to enable search for Internet based publishing site: 3 application servers, 2 WFE servers, 1 sql server cluster.

In the 3 application servers :

• one server running - central admin & other services.
• Two app servers are now is empty there is no service applications.

Search Topology and Search Components : App 1 & APP 2 :

• Admin component
• Crawl component
• Content processing component
• Analytics processing component

WFE 1 & WFE 2:

• Query processing component Index component

Questions:

1. Is it good practice to create Query Processing components and Index partitions in WFE servers?

2. If I move Query Processing components to Application servers, are users able to search the content?

Answer 1

Move the index component to the App server. The Index component can be kept separate from WFEs as it is the search index which is accessed by crawl and analytics components and can be kept different from WFE server processing (which is to serve user requests). Index Partitions are not recommended on WFEs.

You can continue to keep the Query components on WFEs or move them to App server. Both architectures are followed. The reason query components can be kept in WFEs is that when user issues the query, they go through the query component first. If it is configured on App server, it does not affect search. This is just logical placement of services based on available infrastructure.