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 5207DDF56 for ; Wed, 7 Nov 2012 19:15:14 +0000 (UTC) Received: (qmail 19989 invoked by uid 500); 7 Nov 2012 19:15:08 -0000 Delivered-To: apmail-hadoop-user-archive@hadoop.apache.org Received: (qmail 19873 invoked by uid 500); 7 Nov 2012 19:15:08 -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 19846 invoked by uid 99); 7 Nov 2012 19:15:08 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 07 Nov 2012 19:15:08 +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 (nike.apache.org: domain of rarecactus@gmail.com designates 209.85.219.48 as permitted sender) Received: from [209.85.219.48] (HELO mail-oa0-f48.google.com) (209.85.219.48) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 07 Nov 2012 19:15:01 +0000 Received: by mail-oa0-f48.google.com with SMTP id h2so2225135oag.35 for ; Wed, 07 Nov 2012 11:14:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=NU7QYHDH4RGXzZa0cuEQj8oH+kD8O7tmRw0so1KQM6k=; b=I27oBN+36llrpq3Se+pVmeRX2xlymHSNUXbkLnhgyCpyrdSQuniYpOxwOu0p+gcy8M aSmlGVRlj0no8y7G5pakVics9adjyrakzbdwi7G8ls9RGo9yWGD+9vvS0Xvgwe6E+moN wwiRElXy6uVK6Qoec/E60ZHQsrJeKz/6Hkt0+5daVwqC8V3okd6dQENdzb+ukaQc/JRZ zbNorT8d8oxIXx22HYgD/kYwTI3XDQGRalSL6xAYdm9nvbKOdEJLwQFjzStzN5CJkZKw LyA81wFoZEdGqlngnJiQY2Yypx9ExR6VKbck0pdYQbcEG4EVBfVb2ecQmvhz3La75L1e NU8w== MIME-Version: 1.0 Received: by 10.60.171.41 with SMTP id ar9mr2973181oec.16.1352315681077; Wed, 07 Nov 2012 11:14:41 -0800 (PST) Sender: rarecactus@gmail.com Received: by 10.76.99.75 with HTTP; Wed, 7 Nov 2012 11:14:41 -0800 (PST) In-Reply-To: References: Date: Wed, 7 Nov 2012 11:14:41 -0800 X-Google-Sender-Auth: z5Ph43fTSL-QSf1mExM2oc8qaIg Message-ID: Subject: Re: same edits file is loaded more than once From: Colin McCabe To: user@hadoop.apache.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Checked: Checked by ClamAV on apache.org Hi, If you want to learn more about HA in HDFS, here are some slides from a talk that Aaron T. Meyers and Suresh Srinivas gave: http://www.slideshare.net/hortonworks/nn-ha-hadoop-worldfinal-10173419 branch-2 and later contain HDFS HA. cheers, Colin On Sun, Nov 4, 2012 at 1:06 AM, lei liu wrote: > I am using hadoop0.20.2, now I want to use HDFS HA function. I research > AvatarNode. I find if the StandbyNN do checkpoint fail, when next time the > StandbyNN do checkpoint, the same edits file is loaded again. Can same > edits file be loaded more than once in hadoop0.20.2? > if not, what is the harm? > > Thanks, > > LiuLei >