title: Confusion in Apache Nutch, HBase, Hadoop, Solr, Gora
body: <p>I am new to all these terms and given some time to understand it. But i have some confusions in it. Please correct me if i am wrong.</p>
  
  <p>Nutch: It's for web crawling, using it we can crawl web pages. We can store these web pages somewhere in db.</p>
  
  <p>Solr: Solr can be used for indexing web pages crawled by Apache Nutch. It helps in searching the indexes web pages.</p>
  
  <p>HBase: It's used as an interface to interact with Hadoop. It helps in getting data at real time from HDFS. It provides simple SQL type interface for interacting.</p>
  
  <p>Hadoop: It provides two functionalities: One is HDFS (Hadoop data file system) and other is Map-Reduce functionality taken from Google algorithms. Its basically used for offline data backup etc.</p>
  
  <p>Gora and ZooKeeper: I am not sure of.</p>
  
  <p>Confusions:
  1). Is HBase a key-value pair DB or just an interface to Hadoop ? or i should ask, can HBase exist without Hadoop ?
  If yes, can you explain a bit more about its usage.</p>
  
  <p>2). Is there any use of crawling data using Apache Nutch without indexing into Solr ?</p>
  
  <p>3). For running apache nutch, do we need HBase and Hadoop ? If no, how we can make it work without it?</p>
  
  <p>4). Is Hadoop part of HBase ?</p>