Apache Nutch Expert needed to diagnose the problem with partial crawling.

I have a Apache Nutch 1.7 application running on Hadoop YARN 2.3.0 , I am facing two problems. 1. I have 10 urls(domains) in my seed list Nutch only cralws 5 of them. 2. The 5 domains that are being crawled in step #1 are being crawled only partially , meaning about only 5 to 10 % of the possible pages are being crawled. I believe this is a problem , because of some configuration issues , I have plaed with different values of depth and topN while starting the crawl , but still faced the same issue, I need someone to help me point out the problem.