Return-Path: X-Original-To: apmail-hadoop-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id C9759DFC3 for ; Fri, 14 Sep 2012 06:09:03 +0000 (UTC) Received: (qmail 5407 invoked by uid 500); 14 Sep 2012 06:08:59 -0000 Delivered-To: apmail-hadoop-user-archive@hadoop.apache.org Received: (qmail 4950 invoked by uid 500); 14 Sep 2012 06:08:58 -0000 Mailing-List: contact user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hadoop.apache.org Delivered-To: mailing list user@hadoop.apache.org Received: (qmail 4928 invoked by uid 99); 14 Sep 2012 06:08:57 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 14 Sep 2012 06:08:57 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=5.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [87.230.46.220] (HELO vwp3725.webpack.hosteurope.de) (87.230.46.220) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 14 Sep 2012 06:08:51 +0000 Received: from dslb-188-096-164-240.pools.arcor-ip.net ([188.96.164.240] helo=[192.168.2.107]); authenticated by vwp3725.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) id 1TCP4n-0002hX-A6; Fri, 14 Sep 2012 08:08:29 +0200 Content-Type: text/plain; charset=iso-8859-1 Mime-Version: 1.0 (Mac OS X Mail 6.0 \(1486\)) Subject: Re: What's the basic idea of pseudo-distributed Hadoop ? From: Kai Voigt In-Reply-To: Date: Fri, 14 Sep 2012 08:08:28 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <5B24054F-762B-43EA-824F-9E0641B84584@123.org> References: To: user@hadoop.apache.org X-Mailer: Apple Mail (2.1486) X-bounce-key: webpack.hosteurope.de;k@123.org;1347602931;d6ced092; X-Virus-Checked: Checked by ClamAV on apache.org Hello. Am 14.09.2012 um 08:03 schrieb Jason Yang : > I have a question about how does the pseudo-distributed Hadoop cluster = work: >=20 > As many map tasks are submitted to the pseudo-distributed Hadoop = cluster, does the hadoop run each mapper in sequence ? or does it run = these mappers in different threads or something could be parallel? pseudo-distributed mode is a one node cluster. You have a namenode, a = jobtracker, and a single datanode and tasktracker running. You can = verify with "jps" command. The default setting is that a tasktracker can run up to two map and = reduce tasks in parallel (mapred.tasktracker.map.tasks.maximum and = mapred.tasktracker.reduce.tasks.maximum), so you will actually see some = concurrency on your one machine. Kai --=20 Kai Voigt k@123.org