Return-Path: X-Original-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-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 05AD9F67C for ; Thu, 18 Apr 2013 17:20:33 +0000 (UTC) Received: (qmail 1007 invoked by uid 500); 18 Apr 2013 17:20:28 -0000 Delivered-To: apmail-hadoop-hdfs-user-archive@hadoop.apache.org Received: (qmail 893 invoked by uid 500); 18 Apr 2013 17:20:27 -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 869 invoked by uid 99); 18 Apr 2013 17:20:27 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 18 Apr 2013 17:20:27 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_FONT_SIZE_LARGE,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of doducthanhbk@gmail.com designates 209.85.217.172 as permitted sender) Received: from [209.85.217.172] (HELO mail-lb0-f172.google.com) (209.85.217.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 18 Apr 2013 17:20:21 +0000 Received: by mail-lb0-f172.google.com with SMTP id u10so2935474lbi.3 for ; Thu, 18 Apr 2013 10:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=nsZmcVxd0xXuAEg5lsKshnfN7Gh6yz8qaOAjBartTHY=; b=fKqWwm16i+rurMVfp/uYtXeYtdxfg+ABys1KvFNrEyyo8nYrUO9UfXpL7V48+ONDR2 5pjez5FthrJJiF0KNsLuYQQrILD2dhZEJDH7/pAhHiO91vCKrj5IGjBvH3Y3IDhVz4mT fxX6n07KSCiiRmkRtlDp0maK1H3Ox0TAURsomH9mOO378vC7a5ruOaGtP/GrxhtKWI4V H6IPqqGWKpOtveqWqkmsi53j8jKyUPQR5iumpeIxqnAus6YzFTodWgp0qCSuaYK8lKLY VHvEI3hqSovE/xY05x55CUlP4S9/Cl/AVKcEVrgt2ir43eJIu/ZJsDUlfUrC8LRhe84/ j6mQ== MIME-Version: 1.0 X-Received: by 10.152.27.229 with SMTP id w5mr3743211lag.46.1366305600816; Thu, 18 Apr 2013 10:20:00 -0700 (PDT) Sender: doducthanhbk@gmail.com Received: by 10.114.173.163 with HTTP; Thu, 18 Apr 2013 10:20:00 -0700 (PDT) In-Reply-To: References: Date: Thu, 18 Apr 2013 12:20:00 -0500 X-Google-Sender-Auth: iTHQj_dOuNSGTfj_ONZIweKzKbc Message-ID: Subject: Re: why multiple checkpoint nodes? From: Thanh Do To: user@hadoop.apache.org Content-Type: multipart/alternative; boundary=089e0160a31afdcaf004daa5cfd7 X-Virus-Checked: Checked by ClamAV on apache.org --089e0160a31afdcaf004daa5cfd7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable so reliability (to prevent metadata loss) is the main motivation for multiple checkpoint nodes? Does anybody use multiple checkpoint nodes in real life? Thanks On Thu, Apr 18, 2013 at 12:07 PM, shashwat shriparv < dwivedishashwat@gmail.com> wrote: > more checkpoint nodes means more backup of the metadata :) > > *Thanks & Regards * > > =E2=88=9E > Shashwat Shriparv > > > > On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do wrote: > >> Hi all, >> >> The document says "Multiple checkpoint nodes may be specified in the >> cluster configuration file". >> >> Can some one clarify me that why we really need to run multiple >> checkpoint nodes anyway? Is it possible that while checkpoint node A is >> doing checkpoint, and check point node B kicks in and does another >> checkpoint? >> >> Thanks, >> Thanh >> > > --089e0160a31afdcaf004daa5cfd7 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
so reliability (to prevent metadata loss) is the main moti= vation for multiple checkpoint nodes?

Does anybody use m= ultiple checkpoint nodes in real life?

Thanks


On Thu,= Apr 18, 2013 at 12:07 PM, shashwat shriparv <dwivedishashwat@gma= il.com> wrote:
more checkpoint nodes means= more backup of the metadata :)

Thanks & Regards =C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=20 =09 =09 =09 =09

<= font size=3D"6">=E2=88=9E

Shash= wat Shriparv

<= div>


On Thu, Apr 18, 2013 at 9:35 PM, Thanh D= o <thanhdo@cs.wisc.edu> wrote:
Hi all,

The document says &qu= ot;Multiple checkpoint nodes may be specified in the cluster = configuration file".

Can some one clarify= me that why we really need to run multiple checkpoint nodes anyway? Is it = possible that while checkpoint node A is doing checkpoint, and check point = node B kicks in and does another checkpoint?

Thanks,
Thanh


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