Return-Path: Delivered-To: apmail-hadoop-general-archive@minotaur.apache.org Received: (qmail 50977 invoked from network); 30 Jun 2010 05:48:33 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 30 Jun 2010 05:48:33 -0000 Received: (qmail 63318 invoked by uid 500); 30 Jun 2010 05:48:32 -0000 Delivered-To: apmail-hadoop-general-archive@hadoop.apache.org Received: (qmail 63071 invoked by uid 500); 30 Jun 2010 05:48:29 -0000 Mailing-List: contact general-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: general@hadoop.apache.org Delivered-To: mailing list general@hadoop.apache.org Received: (qmail 63061 invoked by uid 99); 30 Jun 2010 05:48:27 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 30 Jun 2010 05:48:27 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=FREEMAIL_FROM,HTML_MESSAGE,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of fariha.atta.pk@gmail.com designates 209.85.161.48 as permitted sender) Received: from [209.85.161.48] (HELO mail-fx0-f48.google.com) (209.85.161.48) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 30 Jun 2010 05:48:19 +0000 Received: by fxm16 with SMTP id 16so224090fxm.35 for ; Tue, 29 Jun 2010 22:46:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=yvQPCxjb1SNFAb8VEueYYt9gTXOYoT6gY0a8W5rX5bU=; b=tHhd6raNyIOpNwKy9EIx9L0gWA8z+XKuehBOTCLcwuF93sgVmGk7Xambh+u3PfPYxr ZESgFdBIMv6IoEZi29VpZM5YW/iFWwt7osMv2cr0hj1J/WdfnT+KyS8lr9M6tcrgl5bK HKOimyYF/OTVxvA2aXf8KtCAA7DlH7e3CpE1M= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=pfv3tMk92ADOa4H/0AS4pwXPFOEu3fbAu1L+Gk6DzV6yAeJ1OdwJ6pXjcnH9W44JWa nBomAajAfTCKYLC83WWwdsLWgYlTNxBRV/fImMlIKu8P7pVBR/oFV/N3JKusiUHI5bTL La6G8QvkWdWspjBNtVxx+Nv0L5wB3pxBQ/X5w= MIME-Version: 1.0 Received: by 10.223.50.193 with SMTP id a1mr6822581fag.34.1277876819346; Tue, 29 Jun 2010 22:46:59 -0700 (PDT) Received: by 10.223.19.5 with HTTP; Tue, 29 Jun 2010 22:46:59 -0700 (PDT) In-Reply-To: References: Date: Wed, 30 Jun 2010 06:46:59 +0100 Message-ID: Subject: Re: What are uses of taskTracker and JobTracker services? From: Fariha Atta To: general@hadoop.apache.org Content-Type: multipart/alternative; boundary=0015174479ece245ad048a38e194 X-Virus-Checked: Checked by ClamAV on apache.org --0015174479ece245ad048a38e194 Content-Type: text/plain; charset=ISO-8859-1 *Hi, NameNode* serves as a directory namespace manager. It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. It does not store the data of these files itself. whereas a jobtracker manages job-related parameters. "The JobTracker is the service within Hadoop that farms out MapReducetasks to specific nodes in the cluster, ideally the nodes that have the data, or at least are in the same rack. 1. Client applications submit jobs to the Job tracker. 2. The JobTracker talks to the NameNodeto determine the location of the data 3. The JobTracker locates TaskTrackernodes with available slots at or near the data 4. The JobTracker submits the work to the chosen TaskTrackernodes." [source: http://wiki.apache.org/hadoop/JobTracker] Best, Jonna --0015174479ece245ad048a38e194--