Return-Path: X-Original-To: apmail-hadoop-hdfs-dev-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-dev-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 54AA922C6 for ; Thu, 5 May 2011 17:47:43 +0000 (UTC) Received: (qmail 38212 invoked by uid 500); 5 May 2011 17:47:42 -0000 Delivered-To: apmail-hadoop-hdfs-dev-archive@hadoop.apache.org Received: (qmail 38151 invoked by uid 500); 5 May 2011 17:47:42 -0000 Mailing-List: contact hdfs-dev-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hdfs-dev@hadoop.apache.org Delivered-To: mailing list hdfs-dev@hadoop.apache.org Received: (qmail 38143 invoked by uid 99); 5 May 2011 17:47:42 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 05 May 2011 17:47:42 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of harsh@cloudera.com designates 74.125.83.176 as permitted sender) Received: from [74.125.83.176] (HELO mail-pv0-f176.google.com) (74.125.83.176) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 05 May 2011 17:47:36 +0000 Received: by pve37 with SMTP id 37so1551925pve.35 for ; Thu, 05 May 2011 10:47:16 -0700 (PDT) Received: by 10.142.240.14 with SMTP id n14mr1251875wfh.360.1304617636151; Thu, 05 May 2011 10:47:16 -0700 (PDT) MIME-Version: 1.0 Received: by 10.142.231.20 with HTTP; Thu, 5 May 2011 10:46:56 -0700 (PDT) In-Reply-To: References: From: Harsh J Date: Thu, 5 May 2011 23:16:56 +0530 Message-ID: Subject: Re: about how the hdfs choose datanodes to store the files To: hdfs-dev@hadoop.apache.org Content-Type: text/plain; charset=ISO-8859-1 Hello again xu, Apologies over a bad mistake in the earlier post, I believe I had it wrong. The replication is done as you had explained, so do not get confused by my saying that the NN manages it after the writes (I've said this around as well, learnt the right thing thanks to Matthew Foley today!). i.e. Please disregard this: > The writing process originally only writes only a single copy. The > replication is done by the NN later-on (as part of DN commands sent > via heartbeats). -- Harsh J