Return-Path: X-Original-To: apmail-hbase-user-archive@www.apache.org Delivered-To: apmail-hbase-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 1B81D11863 for ; Thu, 3 Jul 2014 07:46:24 +0000 (UTC) Received: (qmail 87236 invoked by uid 500); 3 Jul 2014 07:46:21 -0000 Delivered-To: apmail-hbase-user-archive@hbase.apache.org Received: (qmail 87142 invoked by uid 500); 3 Jul 2014 07:46:21 -0000 Mailing-List: contact user-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hbase.apache.org Delivered-To: mailing list user@hbase.apache.org Received: (qmail 86739 invoked by uid 99); 3 Jul 2014 07:46:21 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 03 Jul 2014 07:46:21 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of olorinbant@gmail.com designates 209.85.212.182 as permitted sender) Received: from [209.85.212.182] (HELO mail-wi0-f182.google.com) (209.85.212.182) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 03 Jul 2014 07:46:18 +0000 Received: by mail-wi0-f182.google.com with SMTP id bs8so1739211wib.9 for ; Thu, 03 Jul 2014 00:45:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type; bh=ytgUo1WWDP/m5T0kqI1R3z8PY8m3zsg9RB2FM2eb1gY=; b=bTju5G9j6nwlQ1w6wTgrqTKTo0izdriboJiLB2lbZX5Z3tuXvs1j/nITfLbwzrLJ7g t+tor8JQkMVvAb7Kpj+qQSj+soa+PdtecxzMBN1IWpHvrC41e03G76V7rhYr/rIlgEaM 943N794aS+1k0NNJ9S5R03kXyB4aDlc8g8JuGOvwlywlYmKnhuQUi+clGO9iNf/aJuwC 7Jy8uNH9zVqo/heJN88mCMvs66dPr+Q+VqIQG8tVMgVUUI9YQhewA/f09L5wXF3vLQ3k 53Zm+Q3Kqx5qFTsV8Ys+yS9a+qdUWpDEOVqmKx3pX57G+vZwLWx0HWmC0T06oFYJmFZj fyuA== X-Received: by 10.181.8.198 with SMTP id dm6mr47657918wid.30.1404373554057; Thu, 03 Jul 2014 00:45:54 -0700 (PDT) MIME-Version: 1.0 Received: by 10.216.86.199 with HTTP; Thu, 3 Jul 2014 00:45:24 -0700 (PDT) In-Reply-To: References: From: Mikhail Antonov Date: Thu, 3 Jul 2014 00:45:24 -0700 Message-ID: Subject: Re: What is the impact if hbase master downs? To: user@hbase.apache.org Content-Type: multipart/alternative; boundary=001a1135ea94d25bbe04fd453247 X-Virus-Checked: Checked by ClamAV on apache.org --001a1135ea94d25bbe04fd453247 Content-Type: text/plain; charset=UTF-8 Hi Yanglin, what exactly do you mean by "system..need to take any failover" - any manual action by cluster admin? Failover happens automatically based on zookeeper timeout for current active master. Currently, hbase cluster has 1 active master and several backup masters. When backup masters notice active master going down, they elect new one, and the new one takes over responsibilities. -Mikhail 2014-07-03 0:40 GMT-07:00 yl wu : > Hi All, > > I've read many articles, including Bertozzi's Who needs a Master, but I am > still confused about the Hmaster. > > If the Hmaster goes down, does the system need to take any failover ? > Or just elect a new master, and the new one can restore all the information > from hbase:meta? > > Best regards, > Yanglin > -- Thanks, Michael Antonov --001a1135ea94d25bbe04fd453247--