building a search engine ??

I am thinking of building a search engine with the grep command for our site. i have my information in a mysql db, but i am putting it back into text files. reoson being is that maybe the mysql db goes down under hevy load, and then our site would look like a tree with out branches. So i put all the info in the text files. now for the search engine i have a form that posts of the pattern. on the page receiving this pattern as say $searchpattern i do the command grep --binary-files=without-match -lri "$searchpattern" $path is this too resource intensive ? How does this idea sound ? please let me know. thanx in advance for any replies. Cape Town South Africa