Return-Path: Delivered-To: apmail-hadoop-general-archive@minotaur.apache.org Received: (qmail 67637 invoked from network); 1 Mar 2010 19:03:25 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 1 Mar 2010 19:03:25 -0000 Received: (qmail 56218 invoked by uid 500); 1 Mar 2010 19:03:23 -0000 Delivered-To: apmail-hadoop-general-archive@hadoop.apache.org Received: (qmail 56170 invoked by uid 500); 1 Mar 2010 19:03:23 -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 56162 invoked by uid 99); 1 Mar 2010 19:03:23 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 01 Mar 2010 19:03:23 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=10.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [209.85.222.181] (HELO mail-pz0-f181.google.com) (209.85.222.181) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 01 Mar 2010 19:03:16 +0000 Received: by pzk11 with SMTP id 11so2213186pzk.9 for ; Mon, 01 Mar 2010 11:02:56 -0800 (PST) MIME-Version: 1.0 Received: by 10.142.66.10 with SMTP id o10mr2767129wfa.321.1267470176102; Mon, 01 Mar 2010 11:02:56 -0800 (PST) In-Reply-To: <4c7b1781003010821w68336d83x3ebcfd1b2939b940@mail.gmail.com> References: <1703587b1002281345k118d980al3ec458cd0d74d343@mail.gmail.com> <4c7b1781002281418k578fabb4n81778bb0890e5c90@mail.gmail.com> <4B8B9B80.3070509@apache.org> <4c7b1781003010821w68336d83x3ebcfd1b2939b940@mail.gmail.com> Date: Mon, 1 Mar 2010 11:02:55 -0800 Message-ID: Subject: Re: Adding hard-disks to an existing HDFS cluster From: Eli Collins To: general@hadoop.apache.org Content-Type: text/plain; charset=ISO-8859-1 On Mon, Mar 1, 2010 at 8:21 AM, Marc Farnum Rendino wrote: > On Mon, Mar 1, 2010 at 5:48 AM, Steve Loughran wrote: > >> Best of all: a secondary namenode to get the streamed event log, as that >> will mean your cluster restarts faster. You do not want to lose your NN >> data. >> > > If the NN data is lost, all the HDFS data is functionally lost, right? > Yes, it is important that the NN metadata (the fsimage and edits log) are stored reliably. There's a great chapter on HDFS administration in the book Hadoop: The Definitive Guide. Thanks, Eli