Difference between Managed Properties in FAST search and Metadata Properties in SharePoint search?

Question

I have a SharePoint 2010 with FAST search installed. In the FAST Query SSA, I can find 2 places contain "Metadata properties":

1. /searchadministration.aspx, under Queries and Results > Metadata properties
2. /searchadministration.aspx, click FAST Search Administration (/_admin/search/extendedsearchadministration.aspx) > Managed Properties

My guess is I should use Managed Properties for my FAST Search customization, however when I try to add new properties and map to crawled properties, I found that some crawled properties only can be found in "Metadata properties" but not in "Managed Properties"

I have read this article about crawled properties http://searchunleashed.wordpress.com/2011/08/24/understanding-crawled-properties-managed-properties-and-full-text-index-part-1/ in my opinion, the crawled properties in both section should be the same.

Am I correct?

Answer 1

in my opinion, the crawled properties in both section should be the same.

You are not correct. FAST Query administration page has two section with access to managed properties and even link to Content Sources (under Crawling).

The reason for this is the fact that People Search does not go through FS4SP but instead uses the built-in SharePoint Search. When the FAST Query SSA receives the queries, it sends queries regarding people to the People Search module in SharePoint and sends all other queries over to FAST. You can open for edit the only content source and find sps3://servername in list of start addresses, it means people source.

And Metadata properties (under Queries and Results) also related to People Search only and this is a difference. If you want to customize FAST properties, you should use Managed Properties link (under FAST Search Administration at the top).