Crawl Impact rule vs Crawl rule, Exam question 70 - 667

Question

Can someone confirm if am right for this question as I tried two practising exams and they both are giving me "Wrong answers"

You have a sharepoint server 2010 sp1 server farm.

You have a front-end Web server and an application server.

You discover that when the application server indexes content, it takes a long time for the front-end web server to respond to the user requests.

You need to reduce the number of items that the application server can index simultaneously.

The solution must ensure that all content is indexed.

what should you configure?

1. Crawler impact rules
2. crawl rules
3. host distribution rules
4. search scopes

Now claimed answer is number 2 crawl rules, but in central admin setting comes under crawl impact rule,

Also if someone highlight me what host distribution rules are other then we use them when we have more then 1 crawler databases.

Answer 1

I think answer no. 1. Crawler Impact rules is correct, explained here.

More about Crawl rules on Technet

More about Crawler impact rules on Technet

[Edited]

Host distribution rules are used to associate a host with a specific crawl database. When you add a host and apply, if the host is already distributed to a crawl store, the crawler will be paused and the content will be physically moved and assigned to the crawl DB you select after selecting Redistribute Now button below. This is a resource intensive operation.