Return-Path: 
 <dev-return-38904-apmail-hbase-dev-archive=hbase.apache.org@hbase.apache.org>
X-Original-To: apmail-hbase-dev-archive@www.apache.org
Delivered-To: apmail-hbase-dev-archive@www.apache.org
Received: from mail.apache.org (hermes.apache.org [140.211.11.3])
	by minotaur.apache.org (Postfix) with SMTP id CBC3A10B4D
	for <apmail-hbase-dev-archive@www.apache.org>;
 Fri, 28 Jun 2013 00:03:57 +0000 (UTC)
Received: (qmail 35877 invoked by uid 500); 28 Jun 2013 00:03:54 -0000
Delivered-To: apmail-hbase-dev-archive@hbase.apache.org
Received: (qmail 35724 invoked by uid 500); 28 Jun 2013 00:03:54 -0000
Mailing-List: contact dev-help@hbase.apache.org; run by ezmlm
Precedence: bulk
List-Help: <mailto:dev-help@hbase.apache.org>
List-Unsubscribe: <mailto:dev-unsubscribe@hbase.apache.org>
List-Post: <mailto:dev@hbase.apache.org>
List-Id: <dev.hbase.apache.org>
Reply-To: dev@hbase.apache.org
Delivered-To: mailing list dev@hbase.apache.org
Received: (qmail 35711 invoked by uid 99); 28 Jun 2013 00:03:54 -0000
Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136)
    by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 28 Jun 2013 00:03:54 +0000
X-ASF-Spam-Status: No, hits=1.8 required=5.0
	tests=HTML_FONT_FACE_BAD,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS
X-Spam-Check-By: apache.org
Received-SPF: pass (athena.apache.org: domain of joarderm@gmail.com designates
 209.85.220.181 as permitted sender)
Received: from [209.85.220.181] (HELO mail-vc0-f181.google.com)
 (209.85.220.181)
    by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 28 Jun 2013 00:03:50 +0000
Received: by mail-vc0-f181.google.com with SMTP id lf11so525874vcb.40
        for <multiple recipients>; Thu, 27 Jun 2013 17:03:29 -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=Pmby3YyD7vbc8CtDb2Edin9WGwZjaPA76/cnvAcd8DU=;
        b=E91lXelYMMpL5i7zDnD0TJKfEQDc8fUCG89c5X76ZpUJrQHUZ/DqWYR1X6YFmxHBqd
         ujHwyTYI7BbLYbA7NkdWc9Ac8pQNaG838sBxRFseBNNYLdypo/GdE9syNW0EsHlSVXfQ
         wUHe3PGutWoHoKGPnJ2JzP7Oe83xx/d1URTGO77f3iqX+0ZVFIdKcg6dsfTUmprW8gpy
         DfUfdODMtVME450IM78IKEY5ztM9a18R6e7hYcdG2OpbqPbHDxmUSVpii+Yvbh+lHCAe
         wWOUUORRrdZfRWQgfV6xLPmfBY5hMkEeuSiloqnjYlbTJsRo5VovNUGnwAn4TtavojyK
         rcOA==
X-Received: by 10.58.15.193 with SMTP id z1mr4524653vec.40.1372377809326; Thu,
 27 Jun 2013 17:03:29 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.220.61.140 with HTTP; Thu, 27 Jun 2013 17:02:49 -0700 (PDT)
In-Reply-To: 
 <CADcMMgHmp4as4_VF4F665hYY54hhQeK3r0N4d4bC5HcyWZ9cSw@mail.gmail.com>
References: 
 <CAM4M=K6rZ6hMLRGoE1znvbFsc2skgUYaRxEf5=H1eg31iV189A@mail.gmail.com>
 <CADcMMgHmp4as4_VF4F665hYY54hhQeK3r0N4d4bC5HcyWZ9cSw@mail.gmail.com>
From: Joarder KAMAL <joarderm@gmail.com>
Date: Fri, 28 Jun 2013 10:02:49 +1000
Message-ID: 
 <CAM4M=K4qWdJDybWVdk6ixJQ=DRVD4sCXC2X6m7EUv7GpsaBa5w@mail.gmail.com>
Subject: Re: Adding a new region server or splitting an old region in a
 Hash-partitioned HBase Data Store
To: dev@hbase.apache.org, "user@hbase.apache.org" <user@hbase.apache.org>
Content-Type: multipart/alternative; boundary=047d7b5d9589d298b404e02b9b85
X-Virus-Checked: Checked by ClamAV on apache.org

--047d7b5d9589d298b404e02b9b85
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Thanks St.Ack for mentioning about the load-balancer.

But my question was two folded:
Case-1. If a new RS is added, then the load-balancer will do it's job
considering no new region has been created in the meanwhile. // As you've
already answered.

Case-2. Whether a new RS is added or not, an existing region is splitted
into two, then how the new writes will to the new region? Because, lets say
initially the hash function was calculated with *N* Regions and now there
are *N+1* Regions in the cluster.

=E2=80=8BIn that case, do I need to change the Hash function and reshuffle =
all the
existing data within the cluster !! Or, HBase has some mechanism to handle
this?=E2=80=8B


=E2=80=8BMany thanks again for helping me out...=E2=80=8B


=E2=80=8B
Regards,
Joarder Kamal

On 28 June 2013 02:26, Stack <stack@duboce.net> wrote:

> On Wed, Jun 26, 2013 at 4:24 PM, Joarder KAMAL <joarderm@gmail.com> wrote=
:
>
> > May be a simple question to answer for the experienced HBase users and
> > developers:
> >
> > If I use hash partitioning to evenly distribute write workloads into my
> > region servers and later add a new region server to scale or split an
> > existing region, then do I need to change my hash function and re-shuff=
le
> > all the existing data in between all the region servers (old and new)?
> Or,
> > is there any better solution for this? Any guidance would be very much
> > helpful.
> >
>
> You do not need to change your hash function.
>
> When you add a new regionserver, the balancer will move some of the
> existing regions to the new host.
>
> St.Ack
>

--047d7b5d9589d298b404e02b9b85--